Does it run slow all the time or does it run slow when the fire particles are on the screen? I tested it on my old laptop and it seemed rather smooth -- I tried to optimize it as much as possible (except for my stupid fire particles) but I guess I can only do so much.
Don't worry, it's an issue that seems to occur in Game Maker games especially on my computer, I just tried Verge on someone else's computer and the game ran fine and smoothly there!
My own computer is an old laptop, so I'm going to search for updated graphics drivers, I suspect my drivers don't support some feature of Game Maker.
I just wanted to tell that I found out how to increase the speed on my computer. I updated DirectX and reduced the debug output (which I use when I develop games), and remembered I had to try some Game Maker games that had been running slowly, so I tried Verge again and now it runs much more smoothly.
And I can tell for sure you have a really good feeling in the jump movement.
(I looked at the debug output and it was about the Direct3D viewport and a render target, which seems like a Game Maker bug, so maybe only the makers of Game Maker can fix it in the future.)