Does Descent count? that's probably the FPS on GoG that's given me the most enjoyment, sadly partly to I didn't enjoy the other FPS games, guess I have weird FPS tastes.

Totally counts. Probably is the best one too actually, because it's still totally original and not dated. Plus the music is great.

I really strongly recommend just going with the ambient music. It sets the mood of the levels perfectly. I can't even imagine playing Painkiller with the battle music on.

Also, don't be afraid to experiment with the weapons. It's easy to get into the habit of just using the shotgun and rockets for everything. And completing the challenges to unlock tarot cards is really worth the effort. Nothing is as fun as slowing the world down x16 and applying enhanced weapon speed at the same time. You'll absolutely shred entire mobs of even the most powerful foes.

Honestly, if you love Serious Sam, you should be able to get at least some enjoyment out of Painkiller and vise versa. But that's completely a personal thing. I'm not demanding that you like the game :3
Only dated thing about it (and it's what keeps me from enjoying the game) is the mouse control. There's no way to get it to feel right.

Well, that's because it was truly meant to be played with a flightstick, silly. Although before I got my latest stick I was surprised by how well it actually played with keyboard only controls (dual movement with both hands), but stick controls are definitely more accurate. So you might get better results forgoing the mouse altogether. ;)

I actually didn't think of Descent because I still see it as an arcadey simulation type without the open space. That said, it is indeed an excellent game and in a league of its own.

thanks! i bought blake stone and duke 3d in the last sale but haven't got round to playing them yet.

and thanks to everyone else for your suggestions as well.

I'm gonna give it another chance, just for this post

Dang. I love Serious Sams in their simple and aggressive straightforwardness, and I was hoping Painkiller is a similar game (that's the impression I earlier got from Painkiller, that it is a similar type of frantic action-FPS). I guess I'll have to try it and make up my mind.

Ps. Do the Unreal Tournament xxxx games offer anything for a single-player gamer? I remember playing the demo version of UT200x (I don't remember the exact number), I loved the graphics and especially the great music, but playing deathmatch against the bots got old very fast.

DL demo of UT 2004 and try the onslaught and assault modes. If you enjoy those with bots, you'll enjoy the game, if not, well...

I love Blood, favourate game on GOG so far.

Ok, but it is only about playing "multiplayer" competitively against bots, not any kind of single-player campaign or anything?

Now I remembered which UT had the great music, UT2003. After playing the demo, I had to hunt down some of the music in Youtube (below). I might even buy the full game for the music alone.

http://www.youtube.com/watch?v=05WLzGHQgZ8

http://www.youtube.com/watch?v=ZbbmPHBXSNg

http://www.youtube.com/watch?v=P4ynjwBZY0w

Yes, it's always MP with bots. And UT2k4's got pretty fantastic soundtrack as well. Anyway, if you are looking for a true singleplayer campaign in UT2004 / 2003 engine, get Unreal 2. Or just get Tribes Vengeance, that one's got a really fantastic, fast - paced SP campaign with interesting story and everything, under the same engine.

Chaser has the dubious distinction, in my mind, of being the first GOG title that truly disappointed me. The start of the game goes really well, setting the tone for a Total Recall-esque plot, but by the time you reach the midpoint of the game you soon realize that you've been fighting the same, tirelessly repetitive generic corridor shooter - with the same tirelessly repetitive textures and architecture - ever since the second level. A lot of the levels were just plain not fun to play, save for the Japanese hotel mission.

The idea of contemporary weapons in a futuristic FPS also loses its novelty fast when you realize that many of them are almost practically identical; I ended up not caring and just used whatever my enemies at the time were using.

To add further insult to injury, the ending is terrible. Not Revenge of the Sith-terrible, or ME3-terrible, but just plain dumb, with the final scene essentially rendering the entire game irrelevant to the course of the plot.