I've only played the first one and I thought it was pretty good.
Combat is fun, tough and brutal, usually done with whatever you can get your hands on (pipes, tool, paper cutters, axes, rebar with concrete, etc). All melee weapons feel powerful, giving a satisfying sound when you bash someone in the temple. You can also counter attack with them but it requires careful timing and the AI can still recover from them quite well and counter back. There are a few guns but they are incredibly rare and only have around 3-4 bullets in them.
Unfortunately, combat is the only way to progress through the levels. The game could have benefited from a good stealth system too, imo.
The collecting evidence minigame is pretty cool though, and can be tense when you want to hurry up in finish because you hear some psycho enemy wandering around the corner.
Levels are a bit on the short side and pretty straight forward, but they are well designed. I really liked the abandoned school, and the shopping mall level with all the mannequins and enemies dressed at mannequins. Couple that with the hallucinations the pc experiences from time to time, and you've got a game whose levels like to fuck with you.
Story is total shit though, I couldn't make any sense out of it. You have to complete all these boring collect-a-thon side-quests to unlock more pieces of the story to read. Meh, it'd have been fine if it was done like in SS2 or something, but here you just collect like 30 slabs of metal or dead birds and then it unlocks a new file in the main menu. It's really stupid, fuck that.