Pros:
Music/Sound - The music in here is really nice. I played for about 4 minutes, and it had enough depth to not get repetitive. Sound effects are good as well.
Art style - visually, it's a nice game to look at. The lit pumpkins for lives are a nice bit of added flair - they sell the art style a lot better than a typical life counter with a number.
Concept - Clear and simple with lots of room for expansion and the possibility for some pretty elaborate puzzles.
Cons:
Character Control - Controls feel like the character has way more mass than he should. Would feel a lot better to play if he accelerated and decelerated faster.
(If using physics-based movement, you can achieve this by increasing the force in the direction of desired motion when the character is moving in the direction opposite of desired motion)
Jump Spacing - It's very difficult to guage where to drop your body (and difficult to land on it when you respawn) since you can't see the entire obstacle. It would be good to zoom the camera out here to show the whole jump when possible.
Cool things you can add:
Respawn Point - Add the ability for the player to choose where to respawn, so they don't have to traverse the entire level to get back to the obstacle again. This may need to be disabled in some areas depending on if there's combat/bosses or difficult challenges where the difficulty lies in traversing them all at once.
Congrats on completing your game and best of luck!