For me, it got to be DUSK. A Doom-like retro style shooter inspired by the greats of the time (Quake, Half Life, …) that perfectly emulates the strengths of the games, also visually and in overall art style, while bringing all of it to life with modern technology and game design.
I only played it shortly, but it seems to have some sort of manipulative matchmaking that makes it look easier in the beginning to hook you to the game.
It puts you against bots. I wish they would name the bots as what they are, bots.
That is my biggest gripe with it.