I generally try to finish a game before I review it, but I really can't with this - between the controls, the lag, and the blurry graphics, playing it feels too lousy to spend the time on.
The controls feel a little sluggish (movement feels slow to start), but my biggest qualm is that you've mapped jumping to the "up" key, which never feels good unless I'm using the mouse to aim (and thus my keyboard hand is focused around one area) or I'm *only* using the arrow keys to interact, and my other hand is idle. Otherwise, having "jump" mapped to a key near shoot, dash, etc would feel much better (like how you have it mapped to a face button in the gamepad controls - it's the same logic).
Music is annoying but easily muted. Don't have much to say about the SFX as I muted it - would be nice if I could mute music and SFX individually, but not a big deal.
Like many other reviewers, the game would lag whenever the graphics got a bit intense. I'm running on a laptop, so I'm not too surprised, but it's still a bummer when I'm playing a flash game and it's too intense for a laptop from this decade. Closing other programs helped with this a bit, but that's a bit inconvenient.
My largest complaint by far is that you've got pixelated graphics at an extremely small scale with a scan line filter on top of it. Everything looks blurry whenever I'm moving, and it both hurts my eyes and makes it hard to tell what's going on. It might work if full-screen mode was enabled and the graphics were scaled up, but as it stands now it's terrible and makes me not want to play it at all.
Beyond that, the game's just sort of run-of-the-mill - the time control mechanic sets it apart from most metroidvanias, but even that's a bit passé in 2D platformers at this point, and there's no real story to pull the player in (unless it's much later into the game and I just haven't reached it yet).