I guess some traps like in I Wanna Be the Guy could make the game more fun. :D Some flying enemies (use "move to object position") like medusas, slowly following the player, could make the game more tense.
You make very cool vfxs. I will use them in a personal game project (top-down action). If you want to see in the future, I'll post the game link here. Thank you for sharing.