Great atmosphere. Scary. Guns. Stupid AI. Pick up loot, bad guys everywhere. Shoot. Great maps. Secrets. Barrels. Fun. Indeed feels like Ye Olden Days of Doom II, Blood and Quake. And yes, there's even monochrome mode and sepia mode for extra "Ye Olden Days" points. (Plus many other color modes that look funny.) The game is exactly what it looks like and that's great.
