Season's Beatings is an incredibly fast one hit kill first person shooter that is best described as Hotline Miami in first person.
Arkshot combines the fluidity and skill of an arena shooter with the lighthearted fun of a party game. It's Quake meets Duck Game. Unreal Tournament meets Smash Bros.
Paranautical Activity combines the classic FPS action of games like Doom and Quake, with the randomness and difficulty of modern roguelikes like Binding of Isaac and Spelunky.