Its a cool game,Like minecraft you place things,but it makes cretures,like a simulation,Wich is cool!
If you want more awsome weird little simulation games= http://dan-ball.jp/en/javagame/
http://jayisgames.com/tag/webtoy Or google webtoy,and also google simulations.Aplets are fun too=http://ccl.northwestern.edu/netlogo/models/community/Zombie_Infection_2
http://ccl.northwestern.edu/netlogo/models/community/ also click models.Well try it out if you want! :D
EDIT:more info on caverns=its a game with elements,and each one makes something,like water on a ceiling,drops down and makes a colony of water peaple,they live on the water ground,and interact with other species,If they mate with a dust person it makes a whole new creature,and so on....