You can hold Space to see what enemies you can eat and those you can't. Every ~5000% max size you can eat (the player's texture is 1x1 pixel and enemies' 2x2 pixel, so it isn't really that big) the world size will become bigger. The transparent circle around you represents how big does an enemy have to be for you to be able to absorb it, it's affected by "forgiveness", which is a variable that defines how much bigger can an enemy be compared to you, default is 1, meaning 2x your default size divided by 2 (100% size, default is 200%) (2 would be 3x).
The title says it, it's a recreation of a game, tho there is more/different stuff, such as world size, I think on that game the enemies just become bigger when you get bigger, on this one I make everything smaller and make enemies' max size bigger.
