Dark Souls is an absurdly good, very easy-to-grasp, fantasy RPG that's a lot like Skyrim.
Just wanna say that if you are thinking of playing Dark Souls, DON'T play it on PC, it was a bad port that was very laggy for no reason at all (Im able to run alot better looking games with no problems yet that one was insanely laggy) and if you find a patch for it or something, then be aware that the game is almost unplayble without a numberpad.
whereas even Angry Joe liked Dishonored enough for it to get to his top 10.
I didn't really get into dishonored enough to be able to play the whole game (the whole sword combat kindof ruined it for me) but I have to say that the graphics used in that game is not up to par with modern day graphics at all and for some people that may come to be a surprise and in some cases might ruin the game.
I suggest Contra. It's an NES classic. And if you enjoy that game you should play Metal Slug too. They're both run and gun games that I think you will enjoy.
I know that Metal Slug 3 is a good, decently long game, but I don't know about the first one and Contra is quite short, about 20 minutes of gameplay, which basicly isn't close to the gameplay time you'd get on modern games.
For PC you must play Portal or Half life. One of the two.
I quite liked portal, but I wouldn't classify that as a first person shooter since you're shooting portals to complete 3D puzzels, but I still found that game to be quite good and at some times challenging, I would reccoment this game for the pc though because for me I felt more involved in the puzzels when I was playing it on the PC then when I was playing it on the Xbox 360 (I think it was xbox 360)
i think any valve game apart from half-life 2 i would suggest
I just got to ask why do you not like Half Life 2? I found it better the HL 1 because the places you had to go were more clear cut and the environments were definatly larger and had more interactive aspects then in the first game. Also the engine was better with the whole pushing boxes.