Gameplay-wise, this is pretty good game. Audio and graphics could of course use some upgrades, but the ones you used aren't half bad. I really liked the sound effects announcing the sun will shoot, which helped with smooth gameplay. I also like how you "forced" player to use the side wrapping. My only problem with it is that for some jumps, I could not see if I should use the side wrap or jump it normally, so I got stuck for a few jumps, trying over and over to use the side wrap. Maybe it is intentional, but it felt a bit bad to me. Another thing that felt a bit weird was the amount of bullets the Sun shoots. It seems that the amount grows with time, but I feel like it would make more sense, if it grew with the current height reached by the player. Last thing, I think that the hit boxes of the terrain were a bit larger that the sprites, so that felt weird for a bit.
But overall, this game was pretty fun. So much so that I have finished it (in my second try with only underwear left XD). Good job making it.