Well, the game has many issues indeed.
Music is good, sure but that's thanks to composers that.
As for the game itself and I am sorry if I sound bit too blunt in here.
It needs work. A lot of work. I can see that you are enthusiastic and that is always a good thing that but it needs a little bit of direction to get it right.
I'll try to break this down for you the best I can and while you don't need to listen to everything that I have to say, I hope you'll at least take couple of pointers with you.
Please understand, I don't do this to disencourage you, I do this because I sincerely care. If I didn't, I wouldn't be commenting at all.
1: Graphics.
Not everyone's an artist and that is understandable. Not everyone has talent for it either.
I do not know how interested or motivated you're in spriting but if improving feels difficult, ask help from others. There's no shame in it.
2: Stage design.
It's pretty haphazard at best to be honest. Right now you don't have much going on in there other than couple of gimmicks and quite honestly,
those gimmicks weren't really that good either. It just wasn't that interesting to play this game.
You need more of a solid plan to make the stage design good. What would be an interesting challenge for a player to accomplish for an example.
When player faces a new obstacle, is that obstacle fun and is there a fair challenge behind it?
Right now, enemies just jump in to your face for pretty much no reason.
If I were to suggest, try using Mega Man as an example when you design stages or mayhaps even do some practice stages with MegaMaker "Yes, it's a real thing that you can download for free, google it." to get a feel around what makes fun stage design and what doesn't.
3: Bullets
Quite honestly, it feels like I'm trying to defeat enemies with a spray bottle.
Distance for something I'm facing at is way too short and it gets even worse if I move in to a same direction at a same time.
4: Make the music justice
You've already got like 3 composers making music for you, you need to make those musics justice.
To understand the theme, what it's alike and build the world around that music so the both of them fits together.
You can't just have good music and some random stage around it. Both music and stage needs to complement each other. That is really important.
Typically composers make music around the stages but in this case, you'll have to make stages around music.
They put their heart and soul to it so it's just reasonable that you do the same. No pressure.
If you take all of this in to an account, I am sure that you'll be able to do something awesome.
I wish you a good luck with your project and if you have any questions or require help with something, do ask.
Cheers.
