I really like the artstyle and music. The game has that arcade vibe that makes you want to try just one more time :)
And finally, some constructive ideas for improvements:
-The default key configuration is imo not optimal, especially for qwertz-keyboards. I would suggest (Left Paddle: F, Right Paddle: J, Shoot: Autofire or L)
-Autofire because you are literally holding the shoot-key for the entirety of the run.
-At the beginning of a new stage your position should reset. (Always both in the center, or always both on the sides)
-You may want to consider to also give the barrier powerup instead of the score powerup when one of the barriers has been hit.
-Score maxes out very early and is usually crushed by the deaths before game over. Another digit for the score counter, no death penalty but a score bonus for every leftover life at the end seem like a good fix to me.
-There is a bug that lets you continue the game without enemies firing back. It seems to be triggered if you lose a life at the same time as clearing the stage and you do not press Revive. It is rare and fun though, so you might want to keep it ;)
-After a game over, the cursor in the menu should default to Game Start instead of Tutorial so you do not accidentally start the tutorial again.
-When you beat the game, it should tell you "The End" or "Congratulations". Opening an empty chest and freezing the game after going through all that trouble was an unsatisfying conclusion to this amazing game.