One level that shows the difference between 60 and 30 fps is the gall spaceport. Platforming gets very hard, and sometimes the character walks by itself... There should be a frame limiter for amd users as well.

Apart from this, the game runs perfectly, and the gog team did a great job once again

I'd like to echo what jojapupo said in that the Gall Spaceport seems to have a physics glitch in which the character will slide uncontrollably while moving often to your doom which makes the level borderline unplayable. I think the higher frame rate is causing this. Is there maybe a game config file you could provide that would allow us to select our own frame rate for the game?
Uh, how do we change it ourselves?

Managed to make it to the speeder level and now the game IS unplayable at this frame rate. Gog needs to provide an optional 30 fps version.

Much thanks, that fixed the speeder level and the broken sliding physics in Gall Spaceport. That tells me the game wasn't originally intended to run at 60 fps, at least not without problems imo. I would seriously consider updating the installer to a lower frame rate.
You must be superhuman, and that's saying something considering how good I was at the original N64 version and its lower frame rate. :P

I have another thought, I wonder if Thiev's fix would work with the long standing physics issues in Interstate 76? I'll have to try that later.

Very interesting. I did the Gall Spaceport level last night and somehow managed to complete it with all the sliding around. That level cost me 5 lives, though. I might just try replaying that level with a 30 FPS limit in place instead. I did think, for the age of the game, that the limit should be 30 FPS, so if that works for me then I will agree that the GOG provided nvidia profile should be changed. I need to give it a try first, though.
I already asked about that (see previous comments in this thread). I would work as it is exactly how I fixed I'76 when I played it a couple of years ago, using a limit of 30 FPS in Nvidia Inspector. However, Thiev says that they updated the game to use a framerate limit of 15-20 FPS already.

The original N64 version ran at a lower frame rate, my guess is that the PC version's physics or whatever didn't take higher frame rates into account.
That's odd, could have sworn I tried Interstate 76 recently and it was running at or above 60 fps. I'll have to give it another shot, but I better not drift off topic anymore, lol.

Edit: Okay i'm stupid, last time I tried I'76 was before they split the base and expansion apart. :P The updated installers might fix it.

Could you please explain me why the droids are hopping up and down like crazy at the first level if it's not because 60fps are too fast? And isn't it possible to offer two downloads for the game - one based on 30, the other on 60 fps? Or would that be too much effort?

Should that be 29.5 or 30.5 for 30 FPS? I have vsync always on and the monitor at 59.7Hz.

Ok, tried both and 30.5 'felt' better, 29.5 seemed less stable, but honestly it is nearly impossible to tell. Either solves the overcaffeinated Probe Droids and makes their speed similar to footage from the N64 version, so I'm sticking with 30.5 for now.

Would still be interested in the official word about the 'intended' frame rate. Back in the day, was this just limited by and calibrated for the hardware of the time, so 'most PC's' would run it at 30ish frames per second? Or was some kind of framerate limit / synching lost with modern hard and software?