BLOXEED: Introduction of Bloxeed

• What is Bloxeed?
• Basic rules
• Garbage lines
• Power blocks
• Tip: Transform Glitch of Power Blocks
• Tip: A quirk in the case cells are floating above Flicky

What is Bloxeed?

BLOXEED is a variant of Tetris, a famous block-falling puzzle game, and was released in December 1989^*1 from Sega Enterprises, Ltd. (later renamed to Sega Corporation). Sega's TETRIS (released in 1988), FLASH POINT (1989), and Bloxeed were considered as a trilogy of Sega's arcade Tetris variants around the 1990s and they were all ported to PlayStation 2 with the title SEGA AGES 2500 Vol. 28 Tetris Collection (released in 2006, Japan only).

The first sequel of Tetris (hereafter oblique Tetris indicates Sega's 1988 variant) was a blockbuster in the Japanese video arcade gaming scene; Tetris had already consolidated itself with attractive mechanics, but this Tetris provided a different feeling of control by adopting lock delay unlike Atari one (arcade, in February 1989) and Nintendo ones (both of NES and Game Boy), which improved maneuverability at higher speed. Tetris's speed curve is well-balanced with the lock delay and it even has vexing piece orders yielded by its unique random number generator. After many people had achieved a maxout (hitting 999,999 points and 999 lines), some of the elite players pursued for the least lines to hit one million points, with or without all clears (Tetris has the power-on pattern, so later people preferred to try minimizing lines without getting all clears). Tetris was one of the very few games that enjoyed longevity through decades in the Japanese arcade industry.

The two descendants were not that popular as its predecessor, but they gave challenges to the super players of Tetris -- Flash Point was released next year. It has no endless mode and instead it consists of 100 stages with fixed patterns, and the objective of the game is to erase all of the flashing cells in the playfield. As you play Flash Point, the patterns of stages are getting more difficult to solve, and the speed of falling blocks getting harsher: Firstly, the level doesn't decrease at the start of every stage after elapsing around 15 minutes with a single credit. Secondly, the speed is fixed to 2G ("G" stands for the unit of gravity that drops pieces 1 cell down per frame (about 1/60 seconds), and 2G is double as fast as the maximum speed of Tetris) after around 25 minutes. Flash Point was the first-ever Sega game to feature double speed^*2.

None of Sega's Tetris trilogy have a button to rotate pieces clockwise, and it significantly restricts the player's maneuvers of movement, combined with 2G gravity. However, Flash Point was eventually conquered (with a single credit, without skipping any stages) by several players with amazing intelligence and staggering skill to create strategies to beat some stages infamous for the possibility of instant death or extremely long steps to dig down the field.

Finally, Bloxeed, the last game of this trilogy, featured a versus mode for the first time, but the solo game followed the endless style of Tetris with two new twists, making this game quite challenging and making the situation drastically changes.

The first feature is constant garbage rising. Playfields of Bloxeed have a gauge with 5 meters on each player's side and once it's filled with red lamps, a garbage line appears on the bottom, repeating in the period of 32 lines. It is easy to deal with during the lower speed, but the cycle of receiving garbage is getting faster and faster as the level progresses. In the end, you have to deal with a garbage line per 2-4 pieces unless you shave lines or use a power block. Moreover, Bloxeed has a "high-speed mode" feature, increasing the gravity from 1G to 2G beyond a certain level; the highest speed with the fastest cycle of garbage makes Bloxeed obnoxiously difficult to survive, as was said to be "too difficult to play it endlessly." (The original quote in Japanese)

Bloxeed also has beneficial items for the player: The items named "power blocks" occasionally appear and help you cleaning your stack or fill lines to boost the score. Some people easily achieved the maxout of the score very early since its release by utilizing the power blocks. Still, though, nobody even came close to the maxout of the line count and the highest record (as of 2020) still stood at 500-and-something and it is enough to conclude that the maxout of Bloxeed is one of the most difficult achievements in the Tetris video game franchise. ^*3

Basic rules

Our readers already know of the common rules of Tetris regardless of variants, so we enumerate the basic characteristics (mostly shared with Tetris from Sega in 1988):

A decimal number followed by F and s (e.g. 60F(1.00s)) stands for frames (in NTSC format, about 1/60 seconds) and seconds. (The example means 60 frames or 1.00 seconds.)

• The size of the playfield is 10 (columns) × 20 (rows), having 1 next piece preview.
• The piece coloring is identical to Tetris: I (red), T (cyan), O (yellow), L (orange), J (blue), S (magenta), and Z (green). Unique colorings in Bloxeed are garbage lines (alter for every 4 lines representing the shape of holes) and Flicky always spawning a cyan cell.
• Only counter-clockwise rotation is available. Bloxeed can operate with up to three buttons, but they all do counter-clockwise rotation. Pushing a button works for a single shot from Flicky and Satellite power block.
• The Rotation rule is the same as Tetris, the strict Sega Rotation. No wallkicks are available.
• If the current piece is touching the ceiling, you cannot rotate that piece. (You can do it for the first time whenever the controlling piece leaves from the ceiling.)
• The maximum value of SCORE, LEVEL and LINES are respectively 999,999 points (6 digits), Level 99 (2 digits), and 999 lines (3 digits).
• Bloxeed's random number generator is reused from Tetris (not exactly identical as Tetris though). However, the power-on pattern cannot be reproduced since the random seed is saved regardless of turning off the power (unless you can wipe the save data, by clearing all data from the service menu, for example).
• Whenever the game ends, you can try another game with the same piece order you received in the previous game as in Flash Point, but note that the seed of power blocks can be different and cannot replicate the selection of power blocks.
• It is already discovered that the piece sequence picked up in a game of Tetris and Flash Point loops at 1,000 pieces and use it again from the 1,001st piece (and in Flash Point, the piece sequence is used for every level for the entire game until you topped out and end the game.) However, The piece order of Bloxeed doesn't loop back at 1,000 pieces. (The author confirmed the fact on 15th April 2024, receiving more than 1,000 pieces in one game for the first time.)
• The speed of soft drop (holding the lever down) is 1G. If the current gravity is 1G or higher, you cannot soft drop and therefore no drop points are scored. [wiki]
• The paramters of delays are following: DAS = 12 frames (0.20s), lock delay = 30 frames (0.50s), ARE (appearance delay) = 30 frames (0.50s), line clear delay = 40 frames (0.67s) and garbage delay = 10 frames (0.17s). [wiki]
• The following tables explain the gravity (speed of free fall) by difficulty (Tab. 1), scoring (Tab. 2), and the duration of forced level-up timer by levels (Tab. 3). Note that, in Bloxeed of Japan version (System 18) the required number of lines to raise the next level is 3 instead of 4^*4. [wiki]

Grabage lines

The playfields of Bloxeed have a meter with 5 lamps, on the right side for Player 1 and the left side for Player 2. The meter is always filling up (regardless of delays other than during power block activation) and whenever the meter is filled up with 5 red blinking lamps and a block is locked without erasing lines, a garbage line will spawn from the bottom of the playfield. The meter is consumed once the garbage line spawns, and it starts filling up again with the constant speed. This is how the garbage lines are occasionally spawning. The exceptional cases are following:

• Usually, when reaching level 10, the spawning and emptying of the meter don't happen even if the above conditions are met. (It looks like that this procrastinating garbage spawn is intentionally programmed but not confirmed.)
• If the highest position of the stack is 17 or more, the spawning doesn't happen and still meter empties, but the meter doesn't stop filling up in this condition.
• Activating a power block empties the meter and the expected spawn is canceled. As long as a character summoned by a power block exists in the playfield, the meter does not fill up.

The garbage is sent by one line per once, and the pattern is fixed and simply looping in the period of 32 lines, as shown in Fig. 1; right-side I followed by J, L, 2 Zs, 2 Ss, left-side I, 2 Os and 2 Ts. For every 4 lines, the garbage lines are colored corresponding to the shape of holes. For the first 24 lines, the position of the hole of the garbages swaps from right to left and from left to right alternately, so when you are solving the holes on one side you should not stack the other side too high, to prepare for the next chunk of lines. Additionally, the last 8 lines have a long center hole, with the last T-shaped hole shifting to the left. These lines are particularly annoying because you usually encounter them for the first time at around Level 20 (unless you are intentionally stacking slow to accept more garbages). Surviving through an entire pattern of garbages is a notable milestone to check how you improve your skill.

The speed at which the garbage meter fills depends on the level, and it becomes faster in the further levels. (Tab. 4) However, the bottom meter takes double amount of time to be filled, therefore it takes 6 times the amount shown in the table below to full the gauge from the empty state. You receive a garbage line for every 10 seconds for the first 10 levels, but after Level 10, the period becomes significantly shorter and shorter, ultimately only 114F (1.90s) are needed to fill the meter at Level 40 and beyond (The speed are the same regardless of difficulty which is adjustable with dip switches).

Power blocks

Bloxeed sometimes offers a piece that contains a cell (with a letter or number on it) called "power block" which will be activated when the cell is cleared. Five different power blocks have different effects, and except "4 Lines", a character will appear in your playfield and you can find some cameo appearances of other Sega's arcade games. The common characteristics of each power block are following:

• The position where a power block is embedded in each tetrimino is always fixed, as shown in Fig. 2.
• Clearing line with a power block awards an additional 5,000 points, regardless of the current level or the difficulty.
• Activating a power block will reset the garbage meter to empty.
• If you clear a power block and other power blocks remain in the playfield, they turn into normal blocks.
• When two or more power blocks are cleared at once, only one of them is effective (therefore scores only 5,000 points). The power block with higher priority is activated. (In Tab. 5, the listed above is more prior.)
• Before a character appears inside the playfield, there is a time lag of about 180F (3.00s). During this time lag, the character stays above the ceiling, but you can move it with rhe lever and even buttons are working. When it lands on the surface, and the lock delay (30F or 0.50s) has elapsed, it takes effect in the case of 16t and bomb, and it disappears in the case of Flicky and Satellite.
• The descending speed of characters is different from the piece speed, as shown in Tab. 6 (Only researched in the Normal difficulty.)
• The period during which the character summoned by a power block is in the playfield does count as the elapsing time of the level timer. (Flicky often forces the level up after dropping a piece.)
• All characters have a 2-height hitbox (you cannot slide them into 1-height space). Their hitboxes are lower than they look like and it causes the character to look as if they penetrated the stack.

There are very few researches on the period and distribution of power blocks. As of now, it is clear that there are four "zones" according to the highest position of the stack of the center six columns, divided into 0-8, 9-12, 13-16, and 17-20 -- these zones are factor to determine how frequently a power block appears and how much is the probability for each of the power blocks. Internally, Bloxeed has a timer (to control the appearance of power blocks; it's always running except whenever a powerup is actively used) and a random seed with the size of 64 bits, with the range of value from 00 to 3F (to determine what powerup should appear taking into account of the current "zone" explained above).

Tab. 7 shows the threshold of the timer. Whenever the internal timer exceed the threshold in the current zone, a power block will show up. As far as the author can guess, this value is possibly increasing level by level and these values apply at Level 0 (or the first several levels, maybe), as we intuitively know that the time interval of power block appearance becomes much longer as we delve into higher levels. Tab. 8 is the list of the probability for each power block. If you want to see what power block can be picked up by the specific zone and random seed, please visit Tetris Wiki's article on power blocks. [wiki, thanks to @bSecondTie]

Tip: Transform Glitch of Power Blocks

Bloxeed has a "transform glitch" when a power block appears in a very special circumstance, even though it might not be adequate to call it a glitch. Before discussing the details, let us see the example of those glitches happening in a game. The glitches in question happen at 0:29 in the movie below when an O piece spawns with 16t attached, and another case is when an L piece with Satellite appears in the next box at 0:42. However, when these pieces come into the playfield, the power blocks are transformed from 16t to 4 lines (at 0:29) and from Satellite to Bomb (at 0:42), respectively.

The logic behind the glitch is so simple: you just keep stacking high in order to reduce the interval of power block spawns, then you let a current piece floating longer than the interval when you have a piece with a power block in the next box. This will cause you receive a power block attatched to the next piece once more, but the current piece cannot remember the kind of power block, and it will be transformed into the last chosen power block. To replicate the glitch, you have to make the playfield 17 or more height and do so during Level 0 (the power block interval is reduced to 5 seconds and Level 0 is the only level you can wait that many seconds for a single piece). When the identical power blocks are picked twice in a row (it will be, most probably, 4 lines), you would not notice the glitch.

You can utilize the transform glitch to try to skip a power block you don't want to activate in accident, or you can even activate Flicky twice in a single level by using this glitch, which requires the next power block to be Flicky then you must erase a line with a Flicky cell in the current piece. (Don't forget that the line clear must be made with a signle if you want to activate Flicky twice in a level, and you must not erase the line combining a 4 line power block, otherwise the 4 lines is activated.)

The basic strategy is to build the center high and distribute pieces to left or right without clearing lines, but if the pieces are piling up on either side, the side cannot be used to kill the time longer than the power block interval anymore, and if you cannot clear the single line with the specific power block when all other conditions are met, it is only to waste the setup. The double Flicky activation strategy with the glitch seems much less probable. That is to say, actually, this "glitch" is an easy-to-undestand specification that there might be only one spot to store the kind of power block in the memory and when you receive two in a row (in a very rare case), the last one is used for both of the current and next pieces, and it is not too critical to break the game. It would be super fun if you intentionally setup the double flicky activations via this glitch and it is at least worth a try.

Tip: A quirk in the case cells are floating above Flicky

Flicky is the weirdest character among the power block because it produces cells and line clears are happening during its activation which is possible by intricate codes in the program. Actually Flicky has a strange bahavior as in the video cited below. Whenever there are cells above Flicky (this situation should be intentionally made) and line clear happens, the cells above her shifts upward for each cell you placed during the line clear animation.

The author attempted to recreate the above mentioned situation several times in order to find how many rows those cells shift this way, and concluded that the number of rows is equal to the number of cells placed to the cleared line during the line clear animation, and this number won't surpass the number of cleared lines.

[*1] Some sources say the game was released in January 1990, but Koji Kenjou (former director in Namco Limited and founder of NOISE Inc.) revealed his archive material that says Bloxeed was operational in December 1989.
[*2] In those days the speed is called as "2 cell move mode" (2セルモード). Bloxeed's counterpart was colloquially named "high-speed mode," but not mentioned in the dip switch guide, stated the switch "NOT USED."
[*3] [*3] During the location tests of Bloxeed, somebody hit maxout of the lines and score of Bloxeed's prototype version. (also see Tetris Wiki - Maxout#Tetris(Sega))
[*4] The line number required to progress a level is 4 in Tetris, Flash Point, and Bloxeed released outside Japan, but the Japan version of Bloxeed is 3. Also, Japan's Bloxeed can adjust this value from 2 to 4 with certain dip switches.
[*5] The high-speed mode can be disabled with the certain dip switch, making this value "1" (equivalent to 1G speed). Note that the factory setting is a prerequisite in the official submission so you have to enable high-speed mode to submit your score.
[*6] As explained above, drop points are zero if current gravity is 1G or higher; for example in Normal difficulty, 5 points per cell is given at Level 8 and 10-14, but not at Level 9 and Level 15 (and beyond).
[*7] All clear bonus applies to lines erased by Flicky and 4 lines as well, but Satellite has a unique system of all clear bonus and there's no bonus by using Bomb and 16 Ton. (as in Tab. 2)
[*8] These scores are constant, regardless of the current level and difficulty.
[*9] Shot(ショット) in the Japanese version.

• https://www.youtube.com/watch?v=wm61N6KkLeo&t=4275s(accessed on 10/04/2024) | 第459回 アーケードアーカイバー コズモギャング ザ パズルスペシャル！(In this video, Koji Kenjou reveals a material that the release dates of several arcade games during 1989-1990. Video starts at 1:11:15.) (YouTube, 11/01/2024)
• https://igcc.jp/kenjo-02-01/#i-3(accessed on 10/08/2021) | 見城こうじが訊く　ハイスコアラー、お気に入りの一作を大いに語る　第二回「闘いの挽歌」前編 (IGCC's article with a quote by Zenji Ishii, a former GAMEST magazine chief editor, in Japanese) (18/09/2020)
• https://twitter.com/subesubemanzyuu/status/1496705935871721477(accessed on 08/06/2022) | Tweet by @subesubemanzyuu (Citing the instruction manual of Flash Point board, "2 cell MOVE MODE" can be found on it) (Twitter, 24/02/2022)
• https://tetris.wiki/Maxout#Tetris_.28Sega.29(accessed on 08/06/2022) | Tetris Wiki: Maxout#Tetris(Sega)(About the maxout of Sega Tetris)
• https://www.youtube.com/watch?v=GW1_pr2vJeY&t=1547s(accessed on 10/08/2021) | フラッシュポイント (Flash Point) 高画質版 (Video from VERTEX-DAN. completing Flash Point without skipping stages in 1 credit) (YouTube, 16/10/2011)
• https://tetrisconcept.net/threads/bloxeed-information.1634/(accessed on 10/08/2021) | Tetrisconcept: Bloxeed Information. (A thread of research in Bloxeed by zaphod77) (14/10/2010)