Well, I got to both new levels, and I have to say, the lava level was wonderful. I actually died while playing it, it has a couple tricky spots.
The way you gotta get the star was neat. Spoilers:
As for the boss, he was also quite hard, but he was also very fun. My only problem is, he needs some opening text to show that hes a boss, as he doesn't feel threatening, except for the tough homing attack.
Get some more threatening music, and give him a couple opening lines if you can, using the same image thing you used for the sign. Like the boss is just walking around, you walk up to him, he says blah blah blah you shall not pass blah blah blah, battle starts.
Keep up the great work.