Atomica Shooter is a free arcade game developed by TopCog for the Android platform. In this game, you play as a sub-atomic universe defender, tasked with neutralizing rogue protons that threaten the universe's balance. The game features 30 waves of enemies, and you need to dodge them while firing dozens of electrons per second and collecting Quarks to acquire new weapons.

Atomica Shooter boasts of over 10,000 possible weapon types, randomly generated from 3 Archetypes, 4 Trajectories, and 11 Attributes. The levels are also randomly generated, and there are seven enemy types to encounter. As you progress, you can unlock ten classes, each with a unique play-style, such as the Positron, Tetraquark, and Photon. There are also 60 achievements to unlock, and you can encounter special levels such as Tank Mode or Ninja Mobs.

The game allows you to create a kaleidoscope of bullets as you fire up to 240 bullets per second. You can compete with friends for a high score or see how far you can get in endless mode. Overall, Atomica Shooter is an exciting and challenging arcade game that will keep you engaged for hours.