Simple premise but executed well.

You're a little fish. Eat fish smaller than you to slowly grow into a bigger fish. Keep eating fish smaller than you. Don't get eaten by fish bigger than you. You win.

I was playing this one time while my then-girlfriend was in the room and at one point I very excitedly exclaimed "Oooh we're getting big, now!" and she told me "no, you never do".
1/5 memory for a silly 4/5 game.

This is one of my absolute fav chillout games, the Intellivision controller isn't so much a problem as it usually is since you're only using the disc, and once you figure out how to take down sharks, you can get into a nice groove and start racking up lives