Flowidia Part Two!

I know game one was rather meh and basic, but do not worry, part two is almost complete with more feature, longer and harder levels, and more secrets!
Feel Free to play number one while you wait for two!
Game 1: Flowlab Game Creator - Flowidia
At first I was simply going to post the finished product of number two, but I ran into a small issue, I am lost in my mind. So please if you can give me ideas of what the final level should be also quick bit of context…Our hero was sorta beaten in game one, after coming back he ventures back through the caves of doom to the black castle for revenge! Level 4 ends at entrance of black castle, so level five will be a battle in the black castle. This is where I’m sorta lost, I have some ideas like 4 dark knights this time and after being defeated the boss appears but I’m not too sure on it. So once again, please give any ideas, even if not for final level!