The best games are never forgotten. Half Life 2 is a pretty good example of that. For those who don't know, HL2 got new life breathed into it recently because of a dedicated modder. This mod known as MMod is a gameplay overhaul of HL2 which apparently took 9 years to complete. I started playing this game again because of that mod.
Does that contain monsters / zombies / spooky things? I can't play games with those, but first person shooters without such are nice, somewhat rare though.
It contains some of those elements but they're not scary as much as they are fun to kill. Half Life has a unique take on the zombie though. Its an alien "headcrab" (aka head humpers in HL2) that bites the top of someone's head and then uses them as a host.
I am not sure that I should go for this next shooter game to play before completing the previous series. I have watch its trailer and it is not that much scary to have.