I think I'll add an option to link jump distance and height. That should alleviate the odd movement problem. But play around with the options a bit, and see if you can't get it to where you like it.

Edit: All right, that's done. Not sure about the flashing... Are you using 8-bit color? I think that might stop it from working. Otherwise, as long as the constant is set, I don't see what could go wrong there.