Sometimes I have a bug where I can't move anymore with some characters. I think it happens when joining two together and then switch to a different one without moving.
I definitely wanted to add enemies which are moving and shooting in different patterns so you have to dodge the bullets, maybe reflect the bullets with the weapon.
Sadly I hadn't the time to add it, but I'm planning to do so in an improved version.
You are absolutely right. I wanted to at least add a indicator where the next enemy will spawn, but I created the enemy spawning just 2 hours before deadline and haven't had time to implement it ;D