Retro Blazer is a Darkplaces (Quake GPL) game that puts you back in the mid 90's FPS age. Complete with no crosshairs, just left/right looking, blocky worlds and sprite-looking enemies, weapons and props, it's a shooter that brings back the fast run and gun gameplay from Doom and Duke 3D!
The backstory is as follows (in classic 90's fashion):
In the vast labyrinth of ARK Island, once elder now Tyrannical Warlord, Lokahndril, has used the island's ancient mainframe entity to create his own army of corrupt androids. R-Blazer, the only survivor of the invasion, infiltrates the labyrinth and uses his foe's own weapons against them!
Battle through the different military installations and vast ruins, all with their own unique enemies, weapons and items. Collect items to power up your abilities to make yourself stronger and more powerful, only then can you put and end to the Warlord's hunger for power! We love the look of this.
You can check out screenshots over at Retro Blazer's website, download the latest release (includes Darkplaces engine and precompiled Windows, Linux and Mac binaries) and check out this gameplay video: