Holy crap that final battle was intense! The first two bosses were kinda challenging but I beat them in about 10 minutes. The final boss took me almost an hour of constant running and gunning. Now THAT'S a final battle. I was a little disappointed in the ending, though. I wish after all that hard work that the end could have been more satisfying. Oh, well.
By the way, has anyone unlocked the extra levels? If so, how are they compared to the regular ones? Are they fun?