I like this - it would be cool to have a more obvious way of knowing when I'm taking damage, maybe a notification or continue screen of some kind when I die, and an enemy health bar!
Took me a minute to figure out how to start - maybe mention the WASD movement controls on the main screen?
I think you could benefit a lot from changing the sound / color of enemy bullets so they're not identical to the player's - that way I could tell what's going on a little easier. Might have better juice if everything was just a bit bigger too! I love the lizard character's wiggly move animation!
