Well done on the project! Huge praise to the graphics + audio design on this. Good variety of enemies and game progression elements. Some room for improvement here:
1. The sword attack mechanic should be the first thing that is fixed. It is slow to trigger (which could be by design, but it didn't feel good). Furthermore, sometimes I'd try using my attack and it wouldn't trigger. This could be because I tested on a trackpad though! So in that case having an alternate button for attack on keyboard would be nice :)
2. The motion controls on slopes felt very awkward. It honestly got the job done, but I felt like I was sliding and not running half the time.
3. What's the purpose of the coins? They seemed like a health system similar to Sonic with the rings. I'd love to see the coin mechanic have a bit more depth -- especially because pirates LOVE COINS. Can you buy bullets? Do you need to pay bribes to reach certain areas? Playing with currency that doubles as health feels like a fun way to leverage this mechanic for all its worth.
All around great job and thanks for the submission!