I usually don't like pixel shader but it fits well here. Color pallete and overall visual and audio estetics are pleasing.
After reacheing first milestone my ship dissappeared and other ships started to fly over sea at different angles and boss was instakilled. Something inside of me thinks what my ship fell at the left corner of the screen and ship tried to look at something at the bottom of the map.
Also, I've managed to hurt myself with my own bullets. Usually, I do different collision layers for player and enemy to fine tune that.
Overall, I really enjoyed the game!