Wow, I loved it! I too chose the mailman theme, which is why I clicked on your title. I really like how you made the player sprite move without redrawing the animations, just by tilting and squishing, and for me it totally WORKED. He was really cute, even asleep! I thought the tilemap, puzzles, and coin/spike elements were all super well used and cohesive. Yes, it was difficult to figure out some things, but I stuck with it, specifically in level 2 when I had to make a diagonal jump off the start block and get the coin without taking damage. I almost gave up again in level 4, but hung in there, because I knew that the creator would have made it doable, and it was! It just demanded precision, not sloppy hoppy platforming. I thought this was really well done and fun! 
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Thank you really much for the comment! I am so happy seeing you had a good time with the game; this kind of thing makes me want to keep doing this. The criticisms I received were very deserved though, especially concerning the learning curve, so I'm hoping to get that fixed on a possible full release in the future.