I'm curious if anyone else has troubles climbing up steep slopes on the GOG version of MM7. I seem to not be able to climb certain hills on the GOG version, when I could when I used to play on the disk version. The easiest example I can explain is that I could climb up beside the waterfall on Emerald Island, but when I play on the GOG version I can't climb up and I have to take the long way up.

Just wondering if anyone has noticed anything similar.

The GoG version couldn't be the culprit, but the fact that it's running on newer machines (as compared to the ones the OP ran the disc version on) could be.
If I'm not mistaken, there are some rounding issues that manifest themselves on newer processors that caused minute changes to movement and jumping (which is why jumping in the beehive in MM8 was much more difficult). This was fixed by Greyface patch according to its readme, but I never used it so can't confirm.

From the readme: As for the OP's issue, I just tested MM7 on my PC (GoG's version) and I can easily climb the hill next to the waterfall. You must first jump on the hill, you can't just start walking immediately, but once you do jump you can easily climb up the remainder of the way.

This was the case in most climbable hills in MM6-8. I don't know if it was any different on old machines and whether this is part of the rounding issues mentioned in Greyface's patch though.

I have no idea whats causing the problem. I have Greyface installed. When I jump at the hill it doesn't help. I just end up hanging 2 feet off the ground, not moving up or sliding down. Wiggling side to side doesn't help. I know how to properly climb hills like these, there's something else that's stopping me.

Zig Zagging helps. And you put Jump on "S" as a chosen spell. When you feel like you stalling, hit the "S" for a boost. Hope that works.

From what he wrote, the OP knows what he's doing that doesn't help him. And since he's not sliding down either, it looks like a bug or glitch. Hmmm... have you tried reinstall? Without Greyface patch?

Hello,
Have you tried playing with the option for the turn rate? Try the different options to see if that makes a difference.

Could be right. But I have had to use in M&M 7 "Jump" several times quickly to get moving upward again on some of the steeper Mountains. How it works for Pensalesman

So I've uninstalled and reinstalled everything. After messing with different setting I was able to climb up hills when I ran the game in Software 3D mode. I was not able to climb the hill when I ran the game in Hardware Accelerated 3D.

So I guess it's working properly, but I'm confused why it only works in software 3d.

Hardware mode doesn't work properly in MM 7/8. It was always glitchy in original versions back in time too.

Interesting. Glad it worked in the end.