Frame rate

Is there any way to fix the frame rate? Mine is all over the place.

Your frame rate is "every where"? I assume you mean it's low, and the only way to fix this is to get better hardware.

Yeah, or close some windows.

I've experienced that the game ran really slow in window mode.

Full screen was very smooth though.

Mine's perfectly fine, it's probably just your system struggling a little. Try closing all un-needed processes (apps) and running in fullscreen. Check if there's anything running on your taskbar you don't need, or if your Anti-Virus is/was scanning.

The game can unfortunately run a bit slow with some graphics card. That's why I point out twice at the game page to try the demo before you purchase the full version!

the only time it has slowed down for me, is on one of the early planets where there is a speed run to open the computer things in alphabetical order. Picking up the fly powerup makes the game chug a little.

The problem wasn't that it was being slow, it kept changing speed which can be annoying if you're trying to avoid bullets, sometimes it seemed to be going too fast. It's not so bad now though.
On the plus side slow speed helped with the challenge planet.

And I did try the demo first, I'm not that stupid