I went ahead and paid for the game, the first time I've ever done that for a flash game. I really enjoyed the demo, and definitely rate it highly on its own merits... worth the money to encourage this developer to put up more content.
Just take out his mana and he does huge damage to himself to restore it, other than that you just have to survive... Way easy.
(If we are talking about the same baron, I have not finished so maybe he is harder next time)