Really love the atmosphere of this! It's definitely got that Earthbound feel with the background and effects, but also mixed with some Undertale-like combat. As others said, the visuals are impressive, especially the UI!
A few things I wanted to point out:
- I would consider giving the player more control over their jumps (tapping jump performs a small hop), as it really helps make movement feel a lot more responsive!
- I was also a bit confused in the beginning on how to attack and such, as it wasn't that clear at first. Perhaps as the first attack only, you could pause the screen when the line is in the center with a "Press Space!" or "Attack!" prompt as a quick and simple interactive tutorial. And maybe the enemy health bar could flash red to indicate getting hit.
- Adding to the "speedy bullets" feedback as others have said, perhaps a way to circumvent this, is to have a bullet that gradually speeds up. Of course, there should be a limit to how fast it should go, but just an idea!
Overall, great job with the game!