The foundation is there, needs more work though
A workable game, but its not very fun. some tips:
1) Faster pace. Its waaaaay to slow for a game of this type. try having a faster fire rate to start and have the ship and enemies move a lot faster.
2) make the screen more vertical. with the faster pace, you'll want to give the players more time to see enemies coming. flip the dimensions and that should do. you'll also want to re-scale everything so that it fits.
3) UI that doesn't blend in. basic text for UI is pretty bland. could barely make out my score. add more flair to it so that it pops out and i can quickly glance at my health, score, and whatever else i need to know quickly so i can go back to playing the game.