[TAS] Space Invaders arcade 5490 points on Wave 1 (15 saucers)

Channel:

Prog61

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Published on February 28, 2020 8:18:21 PM ● Video Link: https://www.youtube.com/watch?v=PXr0BnmMVG4

Game:

Space Invaders (1978)

Duration: 6:49

1,976 views

28

Tool-assisted superplay (TAS) of Space Invaders arcade 5490 points on wave 1

Goal of the TAS:
-Get the maximum possible score on wave 1

Notes:
-It is possible to shoot 15 saucers on wave 1
-As you probably know, the saucer give a mystery bonus that is not a big mystery anymore.
The sequence of score is:
50, 50,100,150,100,100, 50,300,100,100,100, 50,150,100,100
The value of the bonus is taken from this table, but change for the next value each time the player shoot a bullet.
The saucer appear every 1536 ($600) frames, so every 25.6 sec.
The timer reset at the start of every wave except for wave 1 where the timer wait for the invaders to drop down a row before starting.
-It is not required to shoot the saucer as soon as possible because the timer for the next saucer start when the saucer appear on the screen, not when it is shot.
-The timer stop when the top row of invaders is 3 row from the bottom. So when you have to shoot the before last row of invaders, no saucer can appear from there.
-The optimal number of columns for the invaders to take the longest time to reach the bottom of the screen is 7.
When there is 11 invaders wide it take 17 steps to reach the other side of the screen.
Each frame one invader move one step, one after the other.
When all 55 invaders are there it take 935 frames to reach the other side of the screen (55 * 17)
Each column is 8 steps wide.
If you shoot one column from any side of the formation (not in the middle) the invaders will take 8 more steps to reach the side of the screen
So, 50 invaders, 17 + 8 = 25 steps then 50 * 25 = 1250 frames to cover the width of the screen
Then:
11 columns: 55 * 17 = 925 frames
10 columns: 50 * 25 = 1250 frames
9 columns: 45 * 33 = 1485 frames
8 columns: 40 * 41 = 1640 frames
7 columns: 35 * 49 = 1715 frames ------Optimal value
6 columns: 30 * 57 = 1710 frames
5 columns: 25 * 65 = 1625 frames
4 columns: 20 * 73 = 1460 frames
3 columns: 15 * 81 = 1215 frames
2 columns: 10 * 89 = 890 frames
1 columns: 5 * 97 = 485 frames
If you shoot invaders in the middle of the formation, there is less invaders to move so they will take less time to reach the side.
For example if you shoot 2 column in the middle of the formation, the formation is still 11 invaders wide but with less invaders to move so:
45 * 17 = 765 frames, conclusion, the formation will drop faster, you will not have time to shoot 8 saucers.
Example from a video I saw: shoot the 3 right columns so that the formation is 8 invaders wide. Then shoot 2 columns in the middle to make a safety gap.
With 30 invaders remaining in the formation: 30 * 41 = 1230 frames, with this method you can shoot 10 saucers, but not more.
-Since that when you shoot invaders the formation move faster, I shoot the 4 columns at the last possible moment.

Thanks to https://computerarcheology.com/ for the invaluable information on Space Invaders.

See https://en.wikipedia.org/wiki/Tool-assisted_speedrun for more information on Tool-Assisted Speed-runs
or http://tasvideos.org for more video.

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