You'd probably like DUSK, which is on sale right now on Steam (not that it was outrageously priced to begin with) and looks and feels like a classic twitch FPS (the devs also have another game called Amid Evil, which seems to do away with the 90's FPS aesthetic and go with a more magical setting, but otherwise keeps the same sort of gameplay). I haven't tried DUSK's multiplayer yet, but the singleplayer modes are great.