Rebinding space to space makes it work, though I'd prefer something like Shift (which doesn't appear to be bindable yet). Also, in case nobody else notices and appreciates it, it's nice how you made the tutorial change the displayed buttons depending on what button is set to the command.
I wonder how you're going to add in all the different elemental attacks. Is it one at a time?
Either way, it's a cool demo. You really nailed that fluid gameplay. Looking forward to where it goes in the future!