No idea what the differences are. GOG only state compatibility for XP and Vista, they do not include Win7. However, many users have got it working under Win7, sometimes with some standard tweaking such as compatibility modes, newer drivers, etc.

What I do know is that the GOG version of MDK1 is the Windows version (Win95 software, D3D, 3DFX) and with no DOS executable. That said, there is a thread that describes the various patches and files you need to obtain to be able to run the DOS version (as the DOS executable can be obtained from official patches) which you can then use with DOSBox. This way you can ensure that you can still play MDK1 in Win7, albeit without the nicer graphics of the Windows versions. I don't know if the Steam version provides the DOS version.

Darn. Guess it's not worth my money until they make it fully compatible with Windows 7 right out of the box. Hate tweaking and that's the reason gog.com is (generally) so great.

Thanks for your reply.

EDIT: Another question. Will Mac version of the first one run only through DOSBox with low resolution? I presume it will...

I don't have a Mac so don't know. I'd guess it would be via DOSBox as that is available for Mac, but I could be wrong. It is probably best to ask GOG support about it.

For the tweaking though, check the threads to see what others have done. It really may just be the whole compatibility mode stuff, which is very simple tweaking.

Well, the MDK page now says it is compatible with XP, Vista and 7 whilst the MDK2 page says XP, Vista and 8. Seems odd that 7 is missing for MDK2 if it runs on both Vista and 8. I imagine MDK2 will indeed run on 7.

I'm playing the Steam version of MDK1, on win7. Works fine for me, and its the windows version, theres no dos version supplied on steam.
I've also run the steam version of MDK2, without issue so far.
I am on win7 32bit though, I dunno if they work just fine under 64bit systems, but on 32, I've seen no issues at all running either MDK game.

I can never get it to go fullscreen I give up with GOg.com

This game has a black border within the game anyway, so even when run in fullscreen, MDK1 will still have some border. Send us a screenshot and we can see if what you are getting is indeed normal.

It's ok I got it to work with DosBox if I had none it was that eay, I wouldn't bother the customer service gu so much lol.
Thanks for offerring to help anyway.

I was going to buy the MDK2 HD version on steam until I read about all the complaints that users had on the forums. I decided as much as I'd love to play it in HD, it's not worth the effort to play it and get it to work if it's not supported like it should be. I've had no problems with any games I've purchased on GOG, so I'd recommend buying it here.