Found a method not mentioned here to get this awesome game working 100% as intended on my modern hardware and thought I'd share.

Step 1: Download cnc-ddraw from below link and extract it to your I76/Nitro install directory:
github.com/FunkyFr3sh/cnc-ddraw/releases
Step 2: Open the ddraw.ini file in a text editor and change maxgameticks=0 to maxgameticks=20. For nitro specifically, also set renderer=opengl instead of auto.
Step 3: That's it. Launch the i76/nitro exe and enjoy the game!

What works:
Absolutely everything!
No acid trip colors
Better graphics
All game cutscenes play
No wobbly wheels for Taurus
No slowdown on jump ramps
Flamethrowers, gas launchers, etc. all working as they should.
Saves can be named
No weird save issues on mission 15/16

Tested on gog I76/Nitro version 2.1.0.17 and cnc-ddraw version 5.1.0.0 on a Windows 7 x64 machine running a 3090. Please report any issues you run into as I can only test on my hardware.

All credits go to FunkyFr3sh for making this wonderful tool that incidentally also fixes many other games including command and conquer/red alert and total annihilation.

The music doesn't work, which makes the game.

That sucks because yeah the music absolutely does make the game and weirdly the music is the one thing I never had issues with.

Can you confirm your gog installer version and os version? I've had some weird crash issues on non current gog versions and non gog versions.

A quick search says that 'no music' happens when using dxwnd which this method/mod does not use. So if you've tried other methods before this, try uninstalling the whole game and mods and reinstalling to a new folder. and if that fails, try setting compatibility to windows 98 which appears to solve it for people using dxwnd.

Thanks! i've owned the game for years and, well, wanted to play this game for many, many years but only with this have been able to get it running!

I do find that the actual game engine runs very slowly, almost as if I had period hardware. :D But, at least I can save most of the time. The staggered frame rate does make getting past the jump level a "10th time's a charm" trick, but at least it's playable.

The closest I've been able to get any Glide wrapper going was dgVoodoo, but it hangs at the "really overwrite save" popup every time, because of the known issues with the DX cursor in the menus. Which is a pity, because it's the only engine that runs fluidly...

No music here either. Any idea?

I'm having no music in game issue aswell, even on clean install using the latest version of the game - and I heard online that DxWnd was supposed to fix the sound issues but even other people seem to have issues no matter what, haven't tried the method in this chat though and will report back but it'll most likley stay the same cus apparently gog updated the game at some point making the game unable to play the music files (or so it seems), can't seem to find any fixes just people with the same issue, clean or modded