Yeah, I had a conversation with another player downpage about that and I'll definitely be reworking the jump before we put this project down. Of all the mechanics, jumping was weirdly the hardest to get right in the timeframe, considering all the nonsense we ended up doing with it ;^.^
The final stage was meant to be a culmination of sorts; yeah, you had been betrayed by the Ambiguously Evil Voice (AEV), but you'd gathered so much power you were capable of handling it. Your thought about disabling walking while carrying the evil soul is interesting though; I might play with it a bit!