Developer: Diffusional Arts
Platforms: PC, Mac
When one thinks of arcade shooter, perhaps the games that come to mind are titles such as Geometry Wars or even the more recent Assault Android Cactus, games defined by the chaotic non stop action and hordes of enemies. Subject 9 stands out from its shooter brethren thanks to tactical high-tech gameplay and more strategic pacing.
You can buy Subject 9 from the developer's site or on Desura or vote for the game on Steam Greenlight.