Sounds potentially overpowered, but it might be fun. Could also imagine a model where it keeps rotating you if you hold down the mouse button. Some of the Jedi Knight games had some crazy combos like that.

it does sound a little OP... how about adding it right here:

http://imgur.com/gpoOkaV

and if someone attacks you on the back while spining you can die or get thrown on the ground like when spidertron's bomb hits you.

so thats why you add speed on the other upgrades, or maybe that will make it bad...

or make it stop at own will so that you dont get hit when a jetpack robot is rushing at you

i dont know, i might make a little animation to demostrate my idea.

I did end up making an animation, kinda like this (ignore poses i just want to demostrate the movement and how it could work if it ends up added in)

https://youtu.be/RO7ntHGmiUk