BLOXEED: Introduction of Bloxeed

Table of contents

What is Bloxeed?

BLOXEED is a variant of Tetris, a famous block-falling puzzle game, and was released in 1990 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*1.

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. *2

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.)

Tab.1 Gravity (frames to drop by one cell)
Level Easy Normal Hard Hardest
0 24 16 12 12
1 20 14 10 10
2 18 12 8 8
3 16 10 6 6
4 14 8 5 5
5 12 6 4 4
6 10 4 3 3
7 8 3 2 2
8 6 2 1 1
9 4 1 1 1
10 12 10 8 8
11 10 8 6 6
12 8 6 4 4
13 6 4 2 2
14 4 2 1 1
15 1 1 1 1
50*3 0.5 0.5 0.5 0.5
Tab. 2: List of Scoring
Level Single Double Triple Tetris S. Drop
0-1 100 400 900 2,000 1
2-3 200 800 1,800 4,000 2
4-5 300 1,200 2,700 6,000 3
6-7 400 1,600 3,600 8,000 4
8-99 500 2,000 4,500 10,000 (<1G*5) 5

All clear*6 10 × line clear point
Activating a power block*7 5,000
Removing one cell by Satellite*7 10
All clear by Satellite (LEVEL+1)×2,000
All clear by 16t and Bomb 0
Tab. 3: Level timer per level
Level Required Time
0 3,480F (58.00s)
1-8 2,320F (38.67s)
9-10 3,480F (58.00s)
11-14 1,740F (29.00s)
15-99 3,480F (58.00s)

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 at 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:

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.

Fig. 1 The pattern of garbage lines (fumen)

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).

Tab. 4: Speed of garbage meter [wiki]
Level Time to turn on a light Time to fill the meter
0-9 99F (1.65s) 594F (9.90s)
10-12 79F (1.31s) 474F (7.90s)
13-14 69F (1.15s) 414F (6.90s)
15-16 59F (0.98s) 354F (5.90s)
17-18 49F (0.81s) 294F (4.90s)
19-30 39F (0.65s) 234F (3.90s)
31-39 29F (0.48s) 174F (2.90s)
40-99 19F (0.31s) 114F (1.90s)

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:

Tab. 5: The list of power blocks, sorted by the priority high to low (4 is the top priority)
Letter Name Effect
4 4 Lines This is the only power block without a character and it takes effect immediately after being activated.
Clear up to four lines of the stack after activation. It clears the 1st, 3rd, 5th, and 7th rows counting from the top, but if the stack height is less than 7, missing lines are ignored. (e.g. If the stack is only 1 height, it clears that line awarding all clear bonus, and nothing happens in the case of 0.)
This line clear is counted as if you cleared lines with a tetrimino (they are added to LINES count, scores a clear point, and also count towards level progression) regardless of how many cells are filled in these lines.
F Flicky Flicky (a blue bird as a protagonist of the 1984 game Flicky) appears in your playfield and descends to the bottom. You can control her with the lever. Flicky has a hitbox with the height of 2 and width of 1.
Whenever you push the rotate button, she drops a cyan cell directly below. If a line is completed this way, it is cleared. (During the line clear delay, you can also stack multiple complete lines to award higher points.)
Lines cleared by Flicky count toward LINES count and line clear points are scored, but if 5 or more lines are cleared at once, the resulting score corresponds to the remainder of the number divided by 4 (A remainder of 0 is considered as Tetris). No more than 8 lines are cleared at once this way, and if other lines are filled but not erased, these line won't disappear unless another line clear process takes place (e.g. by placing a cell, fixing the Flicky, etc.)
Unlike 4 Lines, lines cleared by Flicky do not count towards level progression.
S Satellite*8
A satellite (from the 1987 game SDI: Strategic Defense Initiative) appears in your playfield and descends to the bottom. You can control it with the lever. It has a hitbox with the height of 2 and width of 1.
Whenever you push the rotate button, it fires a shot directly below, and if the shot hits a cell, the cell is destroyed and awards you 10 points regardless of the current level and difficulty.
If you successfully cleared all the cells in the playfield before the satellite touches the bottom, A message "GOOD !!" shows up and gives extra (LEVEL+1)×2,000 points (the maximum bonus awarded in this way is 200,000 when Level is 99).
16 16 Ton A heavy bomb (a weapon from the 1986 game Fantasy Zone with a shape of heavy weight) appears in your playfield and descends to the bottom. You can control it with the lever. It has a hitbox with the height of 2 and width of 3.
The rotate button does nothing. When the heavy bomb is touching the surface and locked, cells of the three columns below the heavy bomb are completely removed.
It affects the cells only below the heavy bomb while the bomb completely removes the cells above it.
B Bomb A red bomb (it's not a cameo appearance of Sega's games) appears in your playfield and descends to the bottom. You can control it with the lever. It has a hitbox with the height of 2 and width of 2.
The rotate button does nothing. When the bomb is touching the surface and locked, the red cells shown in Fig. 3 are completely removed.
The bomb has a width of 2 but the explosion affects the adjacent columns of both sides. Cells in these 4 columns above the bomb are removed, and it digs down up to 3 rows.

Tab. 6: Power block descent speed
Level Required time per cell
0-2 51F (0.85s)
3-4 41F (0.68s)
5 31F (0.51s)
6-9 21F (0.35s)
10 31F (0.51s)
11 21F (0.35s)
12 19F (0.31s)
13 17F (0.28s)
14 15F (0.25s)
15-99 13F (0.21s)
Fig,2 (fumen)
Fig. 3 Effectiveness of B (Bomb) (fumen)

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]

Tab. 7: The threshold of timer (at Lv. 0)
Current Zone Time to appear
0-8 1,200F (20.00s)
9-12 900F (15.00s)
13-16 600F (10.00s)
17-20 300F (5.00s)
Tab. 8: The Probabilities for each power block
Zone 4 F S 16 B
0-8 25/64
9-12 18/64
13-16 17/64
17-20 24/64

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.

このゲームを本格的に始めて数年が経つが、見たことのないグリッチが発生した……ブロクシードは闇ゲー!! #Bloxeed

January 17, 2023

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.

[*1] 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."
[*2] 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))
[*3] 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.
[*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] 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).
[*6] 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)
[*7] These scores are constant, regardless of the current level and difficulty.
[*8] Shot(ショット) in the Japanese version.

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Last update of this page: 03/05/2023