I’ve played through several times getting various performance scores of 999 (three times), 1469, 1249, and something in the 800 range. I don’t think there’s any connection between the performance score and your actions in the game. I got 999 by playing the game the most “obediently” I could; I got the score in the 800s by playing the least obediently, by dawdling, and by running all over the third screen when the crocodile god wasn’t looking.

Since most of this game involves waiting and doing nothing I tried doing that with the final screen. After washing the dishes in the real world the spaceship was still flying through space. I think that genuinely is the end with no ability to relocate to a planet ruled by let’s say a hippopotamus god of some sort.