I really liked this game! It was a fresh take on a classic game design. I didn't finish the game, I'd always die transitioning to the third screen.
Adding some feedback for the things you want the player to do can help reinforce the direction for the player to go. Something as simple as a score that increases, or particle effects/noise on the player killing a worm.
You can increase the intensity by adding some kind of visual or audio cue that a worm has decided you are its lunch.
Congratulations on finishing your game :D