What I liked
- Music - I dug the music. There wasn't a question of whether it fit with what I was seeing.
- Art - It looked very consistent.
What Can Be Improved
- Starting Lives - You should definitely have at least three. As a player, my first chunk of damage taken is a tradeoff for getting an idea of how a level/area is structured and the difficulty.
- Feedback to the player - When I achieve something successful, I expect the game to make it clear that, indeed, I am successful at doing X. In your game's case, the only feedback that I get from killing those initial enemies is that the enemy flashes one or twice. I expected a dying sound from it. I think its especially important in your case because you have that effect where the object is maintaining its velocity for a little bit but sliced. Its really cool, but even when i kill an enemy, i'm a little worried that I missed and I'm about to die.
- Temporary invulnerability when hit - You don't have one and with enemy speeds, its almost certain death if you didn't kill the thing that hit you.
Overall, i think its a really great base with a lot of potential, and if you were to address these simple above mentioned points, you'd notice it immediately as player.
Congrats for being able to submit!