I have a version of the game where spin can be turned off by pressing O on my own site: http://notthefuture.com/centripetal/
It does make the game quite a bit more confusing, but you'll get less motion sickness at least.
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Japser's comment above also inspired me to see what happens when you turn off terminal angular velocity. It's neat! There's a bunch of geometric designs, then ghostly versions of the character appear, before eventually you're spinning so fast that everything returns to normal (but really what's happening is you're now moving 360 degrees each frame). If you go to my site you can just right click -> inspect to activate the console (press Esc if the console isn't there), then type in "gaTopSpeed = 100000;" to turn off terminal velocity, and to get rid of the hint type "terminalCount = 0;".