Been meaning to give this game a try, and yeah, the demo feels kind of like Doom. Fast movement, focus on dodging and switching weapons, and areas with a lot of fodder enemies, too. The level even has some secret nooks and crannies. I'd buy it, but I don't buy Steam games in June... Even though I doubt Doom will see a big discount, patience is key.
Speaking of keys, I just found it adorable that one of the objectives was "Find the blue keycard". Good old Doom there.
The game ran well on my PC with one extremely weird exceptions. The intro logos ran horribly, stuttering all over the place. But as soon as the game was running, it was silky smooth. I wonder what that's all about.