Art was great! You even had screen transitions! And you also fit in a great little tutorial. It's also an interesting and novel take on the theme.Effects like lighting were done well, but may not fit the more light-hearted theme. It seemed more like the lighting in a horror game and made it more difficult to lead the enemies, which is tricky enough.
When I spawned onto the next level, I landed right next to an enemy, who proceeded to spam bullets at me. Enemies should not appear so close to player spawn points. Perhaps the area around them should be a little larger, so you could sneak around better.
Great entry, with just a few tweaks needed to make it really solid. Good job!