I played this game several times and enjoyed the art and what you did with this color palette -- you were able to do a lot with your chosen colors and it makes for a very consistent look and mood.  The parallaxing (is that a word?) backgrounds with wires and fans give great retro vibes.  The bosses here are also great, and it shows that you're skilled at creating them.  The gameplay mechanics are smooth and bug-free.  And I love a game with challenge and this one has it!

I was only able to make it as far as the second boss.  Usually with this style of game and difficulty, I will stubbornly keep at it and enjoy the struggle until I beat it.  The thing that was tough for me here is that in Level 2 (where the bosses begin), there is only a single savepoint at the very start of the level -- at least as far as the second boss.  These bosses are difficult and require repeat plays to come up with a strategy and to get the timing down.  I figured out that it's best to beat the first boss, return to the savepoint and save, and then proceed back through the first boss area and to the second boss -- that way, when I die, I don't have to re-fight the first boss.  But the fight against the second boss is typically over in an instant (it's very difficult), and I then have to make the long trek across two game play areas and one boss area to have another chance at the second boss, which is then over in an instant again.  It wasn't so much the difficulty of the second boss that made me stop playing there -- it was that I didn't get to have repeat tries against it to develop a strategy and get the timing.  Even in a difficult game like MegaMan, e.g., when you make it to the boss and die, you respawn at the boss for as many lives as you have left, and when all lives are gone, only then do you have to start the level over.  So for me, a relatively easy but high-impact improvement would be to put savepoints right before and/or after each boss (perhaps only some of which would refill health?).  Separately, the game looks like it's set up to have metroidvania aspects, but maybe I never reached far enough to see them. 

Sorry for writing a book, but I do so because this looks like it will be a really solid game and I really wanted to play more, and because you've clearly put a lot of good work into it, so I thought the player feedback might be helpful.  I'm optimistic about its future if you keep developing it!