haven't tried "Sticky Ninja Academy", I might need to check it out. You can try and make the game (the infinite mode) have some waves. And after each wave we could have some time so that we can spend out "ice creams" to upgrade a feature. I think that would make it even more addicting (I personally would love to play that version as well, haha). Also, you can't ever go wrong with adding particles, that would add juice to the game. And maybe after some amount of waves, we will teleport to another part of the ship? (as a new map, so that the player is not stuck playing the same level, with different difficulties). And last but not least, if you can make the player more bouncy (as in slimes) that would add more to the fun/gameplay aspect. If you ever plan on continuing the game, I personally think those would make the game feel more polished and I would be more than happy to spend hours playtesting it xD. Great mechanic tho!