Nice work! It was smart that you made the coins non-pickup-able while the player is at full health, and it was smart that the game resets to the main menu upon death.
Next time, consider the colors for the readability of the game. It's great that in this game, red is consistently good as the player color, player bullet color, and coin color. That makes it instantly readable as red = good (even though in most games red = bad). And that it's good that enemies and enemy bullets are both consistently green, but when the enemies die, they release green particle effects, and there's green art on the map. I'd consider making the latter two a different color, because the additional green clutters the player's vision of the game and can make it slightly harder to see incoming enemy shots (i.e., confusing enemy death particles and enemy bullets, or enemy bullets hiding amid the map art).