I enjoyed my time with this game!
I too had some issues with ladders, and with the health bar taking up a sizeable chuck of screen in the first area (then shrinking to normal afterwards).
My advice to you would be to make everything a bit more cramped, or make the player take damage when trying to pass enemies. There was nothing stopping the player from merely running to the end of the level completely unscathed.
Really digging the aesthetic here though, interested to see where this project goes!
:)