If you're worried that your PC won't have the power to run a 10 year old game, you should have thrown it away long ago.

The system requirements are on the game page under the information about the game right next to the large age rating picture.

You can find demos in this linked thread.
The reasons that GOG does not provide demos is that they have not been updated to work on modern systems, and the team has decided that it's not financially viable to do so. As such the demos may give the customer the view that the game does not work on their system, even if it really does work.
Also, they DO list system requirements, it just takes a slightly better eyesight than to read the rest of the text, since the contrast is a tad too low. Attached are screenshots of the game cards for Advent Rising and Duke Nukem 3D to prove my point.

yeah but I have a vague feeling that duke3d doesn't really need a 1.8GHz CPU or 2GB of HDD space. 18MHz & 2MB maybe...
Actually it looks more like the minimums for vista, as if to say "if you can run vista then you can run this"

One of the guys from gog said why the specs where so high on the games. I can't remember exactly what he said, but it was basically dosbox or whatever emulator has higher equirements then a basic game like duke3d so they wanted to make sure they had it higher then needed to cover everything, programs running in the background and all that.

Oh yeah, err on the side of caution but 1GHz cpu with 512MB ram minimum for Broken Sword 2? My 400MHz PDA with 128MB ram can run that flawlessly

Not with vista installed on it :P

there are a few games that won't work on my pc because I need a graphics card with vertex shader 2.0 or something like that. (far cry, painkiller, broken sword 3 won't work I think).
But aside from the gaming end of things, my pc has served my needs well

I'm not your brother.
Quit bitching here. If you want to write your opinions on things that don't really matter, get a blog.

Bearcat, the system requirements are listed below the description of the game. I agree that it would be good if the text could be made bold.
Michaelleung, there's no need to be rude here.

Michaelleung wasn't being rude; if you've read some other posts from bearcat, you'd understand his reaction.

I dont know why everyone's neg repping bearcat but im going to too just for laughs and giggles

Yeah, it's because it's emulated. Emulators need systems that are dramatically more powerful than that which they emulate.

bearcat was already on -8 when they started this thread.

Oh come on, Dosbox isn't THAT demanding.