Scrumptulescent!
First I'll note a few bugs.
If you enter a code to advance to where you left off, the menu music continues to play during the rest of the gameplay over the regular level music. It's really really irritating, so you may want to fix that. Second, the lives never run out, but someone else mentioned that I think. But I actually kind of liked the unlimited lives as some of the levels were really hard and I'd hate to have to keep entering the code and replaying all the levels to get there... Last of all, in the very last level with the girl, "RUN", the water doesn't kill you. I just stayed underwater and hopped up the blocks with ease.
Otherwise, super awesome game man! I really enjoyed this nostalgic game, and the ending was really funny. You should maybe add a "thanks for playing" and "menu", "restart" or something to that effect after the 8-bit people have their conversation, because it just hits a black screen and I wondered for a second if something hadn't finished loading and I should be waiting for something to happen or not.
What else? Oh, the MUSIC my friend. FANTASTIC... I really really loved it. I could have listened to it all day. I don't think there's really anything else to suggest. That game was gold.