Please post any feedback you have about the demo here. This is a huge help for me. If possible post how long it took you to beat and how many times you died. Thanks!
Up until very recently I was 100% focused on getting the game ready to show at a convention, so currently the controller is much more polished then keyboard/mouse, though it is still playable with either. (If you do use keyboard, spin dash is on shift)
Recently I switched input libraries to xinput to get rumble and some other nice features. Unfortunately it broke support for any non xbox360 controller. I have a few ideas on how to fix that, but it's lower priority right now since the game is over a year out from release.
I've made some improvements to the mouse/keyboard stuff. The in game control text now changes depending on if you are using a gamepad or mouse. Also there is generous auto aim with the mouse, though it works a bit different then the gamepad due to the nature of the device.