The keys seems to work on my machine you may want to check if it just happens when you are about to fall then the program may detect you as in the air and not allow you to jump.
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The sticking bullits is a small bug which I just left because it wasent so obvias and seemed to add the challenge of not jumping into them.
The bullits are meant to go randomly left, down, right and up but any bullit meant tobe going down just doesn't move.
After you (bullits) comment I have found the simple error and changed it, here is the file which changed If you want bullits in the correct directions replace it with the current m_maths.bas and re-compile.
Thanks for your comments.