First, some suggestions. 1) Make the collision boxes of the everything a little smaller than the actual sprite, and make the timing a little less tight, so that when the player gets hit, they don't look like the got cheated. 2) When making sprites for your game, make your character at the scale you like, and then while making the other assets, keep the player in the same file for comparison. That way, your pixel art won't be at different scales.
Now, some praise. Congrats on making a complete game in a week! Your content felt just the right length. Your difficulty curve was well done, and even though it was a little difficult, the levels were nice and short, so I didn't have to start a huge section over again. You did a great job introducing mechanics 1 at a time. And the boss fight at the end was a great surprise.