From Ablaze Software:
Part puzzle game and part action game and three modes will keep you clicking. A never-ending quest to reach Critical Mass, and reduce the Atoms to Dust. The concept behind Critical Mass centers on the real life phenomenon called critical mass, where if enough of a radioactive substance explodes it sets off a chain reaction of explosions. In all three game play modes you have the ability to rearrange a set of atoms in an attempt to group them with like atoms. When you have a group of these together (2 or more in Time Trial and Puzzle, but 3 or more in Progressive Mode) you can explode them. If there are enough of them you will achieve critical mass and all the atoms will explode.
Version 1.2 features unspecified improvements and bug fixes.