This is a Wall Defense game where you spin and stop your slot machine to build a creature. Each dial sets the head/body/legs, and as long as you don't hit BUST you will make a creature of some sort that will head out to defeat the enemy.
I'm not sure at this point which monster(s) are stronger and/or if a monster made from 2 or 3 matching parts is stronger than a completely random one. I'm also not sure what dictates which of the three rows the monster will be released. The help in the game tells you enough to play, but doesn't explain much.
Mostly this is a fun random game literally a mix of slots and defense. 2P mode is a lot more fun that playing against the CPU, but mostly you're trying to create monsters as fast as you can and/or monsters with matching parts.