I enjoyed playing this game. I liked the style and I really enjoyed the golden pineapple and the ending that came along with it. I feel the ending really compounded on the meaning of the theme and made it great.
Along with what others have said though, the jumping is an issue, but I believe a lot of issues can be fixed by making the character shorter. The character is simply too tall, so you have to pay attention to both making a jump and hitting your head. Mechanically, that's not that big of a deal, but there is one spot higher up where there is a platform above you, across from you, and a gap in front of you. Avoiding the gap, the platform above, and making the jump leaves a very small window of opportunity before the platform breaks. If the character was shorter, it would help a lot dealing with overhead platforms.
Another spot that would help greatly with a shorter character is failing to make the fourth platform from the start of the game. Currently, if the player misses that platform, he's too tall to go under the third and now has to reset the game. With a shorter model, the player could just go under the third platform, jump onto the second, and now rarely hit reset. Of course these issues could also be fixed by adjusting the platforms, but I feel making the character shorter will be the better option since it's easier and also allows the player to see more of the character while tunneling onto his feet (Nice sandals by the way.)
Having the character shorter will also allow you to have more room to increase the height that the character jumps. There are a few platforms that are closer together but the character can only barely make the height to make the jump.
Whew, anyway! Sorry for the long write up, and hope I didn't sound harsh, but if this is your first entry then you can grow phenomenally. Your game is still very impressive, and again, I really enjoyed the art style you chose for the game and the visuals of the giant pineapple. Good job!