Note to anyone finding that the screen is too big: I zoomed out in my browser and was able to play comfortably, try that.
Really nice to see the buttons assigned to two different attack types, I had a go at a similar thing! What I didn't do was manage to get an inventory system working with just two buttons, good work there.
I think someone else suggested a progress bar to see how far through a level you are, I agree. I was starting to think it was an infinite runner but your first screen is the progression map.
The minecart is a fun, action-adventure style take on the autoscroller. If I didn't know it was from the jam I might have guessed it was an Indiana Jones game on the Commodore 64, nicely done.