The RTA community simply runs until the first congratulations screen and calls that "Beat the game".
https://www.speedrun.com/penguin_wars?h=Beat_the_Game&x=zdnr13x2
I made a run that uses the level select code and reaches the credits.
The time is 4:23.66.
https://tasvideos.org/UserFiles/Info/638769496191691263
Since it's not a legit category I will not try to improve it or submit it.
Some notes:
RNG for the first match changes depending how long you wait on the character select screen.
The speed at which the balls drop down on you when a match starts can also be manipulated this way on the character select screen.
But after that there are no easy ways to manipulate anything. When the opponent tries to push all the balls then I often opted for that to be the match I'm losing whereas when the opponent tries to hold onto the ball and charge, I would try to hit him first and make that a winning match.
There doesn't seem to be the one correct way to win matches since every match is slightly different with the speeds at which the balls drop on you and the opponent's behavior which cannot really be manipulated. The opponent's behavior can be slightly affected depending on your positioning and if you are charging your ball, but that's all I found you can do to manipulate luck.
I see two possible legit categories for TAS.
1) Play all 40 levels, reach the credits
2) Play the first 4 levels, reach the first congratulations screen (same as RTA community)
