Well, this is one of the only games I've ever played where your major buttons are arranged vertically rather than horizontally. Most PC games tend to put their buttons side-by-side, and while I don't know if there's a direct correlation with most people, it seems to make the controls easier to remember and feel more natural. Even after playing through most of the level, I could not quickly and easily switch weapons, and the dash just never got used. I basically had to reduce everything down to jumping and melee just so that I could quickly react to situations without fumbling around to find the button I needed, and I tend to play PC games with a finger hovering over each button already.
I think that the problem with the controls is that the character just moves too damned fast. I mean, look at him. He's covered in bulky black armor, yet moves at a speed I would expect from a crappy Sonic fan-game. Speed like that is fine, as long as there's an acceleration period so that you can make minute adjustments when needed instead of just tapping the button and going flying. I'm not saying to turn this into a direct ripoff, but considering both games use melee, guns, and dashing similarly, I kind of recommend looking to the Mega Man Zero and ZX games as a reference as to player speed and maneuverability. (Damn, almost got through that word without needing spell-check.)
The momentum issue is also present with the space level as well. Given how large everything looks, you would expect the ship to move somewhat slower. I started playing, and immediately started frantically searching for a focus button like in Touhou, to slow the ship down to a more reasonable speed.
You never thought of enemy patterns in the space level? Forgive me if I sound a bit harsh, for it's not intended in any way, but how many shooter games like this have you played? I don't play very many, but patterns are probably the most basic thing they have in them. The patterns themselves are what give each level a unique identity, since as the developer you have the entire level under such powerful control compared to nearly every other type of game in existence. (other than possibly a visual novel) In a shooter game like this, you need to keep in mind that the player only moves at the exact speed you wish them to, giving you intricate control over the timing for absolutely everything.
In a way, you can think about it like choreography. The only thing the player has to show their progression would be the background and the music, so the most natural and basic thing you can do is play that to your advantage. The background needs fitting enemies to match it, while the music can be used to mark timing. As the music plays, it should feel like a conductor leading your level. When the music is fierce, fast-paced, and exciting, the enemies should have the player under heavy fire, weaving and dodging through a maelstrom of bullets and projectiles. When the music slows and ebbs, that's the most natural time to give the player a breather. Not by stopping absolutely everything, but by drastically slowing the rate enemies approach and giving them fewer things to focus on at once, so that they still have to pay attention to avoid a fatal mistake, but they have an easier time of it.
The best example I can think of for something like this would be the final level of the game Genetos. It's a vertical top-down shooter, but in this level, the background music is a non-looping MP3 file. The entire level and its pacing revolves beautifully around the music to the point where it all feels very natural, and you can actually lose yourself in the music while playing, yet still do amazingly well due to how integrated the gameplay is with it. The game's very short, at 5 levels, and freeware, so if you want to take thirty minutes to play through it on easy mode to get an idea, you can. If not, there's YouTube footage without a doubt. I recorded it, myself, but I wouldn't recommend that particular video due to audio lag.
