Control a tiny ball of grey goo with the ability to eat anything smaller than itself. The more it eats, the bigger it gets! After eating a time machine, you'll be sent back to the time of the dinosaurs. There are lots of tasty things to eat back then...
Control the goo with the arrow keys or WASD keys. Eat everything smaller than yourself. The arrow points to the largest nearby entity that you can eat. Avoid larger entities - they will shrink you slightly if you touch them. If you turn on "hard" mode on the level select screen, some entities will even eat you.