Great job! I loved the art style, I don't think I've ever seen something quite like it with the hand-drawn "fuzzy" sprites. I really liked the look of the character sprites especially with their cut-out white outline style. I also found it to be a great incorporation of the theme and it was a lot of fun to reach the characters at the end of levels and walk around through their environments. I guess as one piece of feedback, which may not really be a problem, I didn't realize the smaller mailboxes in the main levels acted as checkpoints until right near the end of the game which meant I mostly started from the beginning of the levels when I died. It was a lot of fun though!