Thanks for playing, and always testing my crap. That game-breaking bug is because I've accidentally left in the 2nd main quest, which was not done, so I've cut it out in a way that causes the game to crash. Got a quick fix.
Also broke the tutorial, so your lock could be because it is a restriction there (Need the player to use a specific attack for a single turn to demonstrate a point real quick)
Enemies are a bit dumb at the moment, so the demo can be completed with minimal issues, but smarting them up will be next.