First of all, I found the pixel art really cute! There's some personality in it.
I'm impressed with the mechanics and physics, especially considering it's your first game! I personally can't even begin to think how to make the line mechanic or the chunk-eating-sword mechanic. Although the levels are short and sweet, I can see you being able to get very creative with things if given more time and all.
That reminds me, very creative way of imbuing the shadow theme on your game! Having the player move around to see more of the surrounding area and all. Very creative!
The music, albeit short, kind of reminded me a bit of Cut the Rope! I'm not sure if it was intentional, but I did see on your GDD that it was one of the inspirations for the game mechanics, so I thought it was kinda cool the music reminded me of it a bit.
Good stuff. Keep making games!