Relic Hunters Zero is a free to play retro arcade action shooter game by an indie developer named Rogue Snail.
"Relic Hunters Zero is a FREE game about shooting evil space ducks and evil space turtles with tiny cute guns. It’s fast, it’s tactical, and feels delicious and smooth to play. Unlock new weapons, characters and relics to defeat the Ducan Commander."
OS: Windows 7 or newer
Memory: 4 GB RAM
Graphics: Shader Model 2.0 compatible graphic card with dedicated memory
DirectX: Version 9.0c
Hard Drive: 100 MB available space
Free download at steampowered.com