I played this one for quite a while, as you've really built out a large playing area, nice work! There's a lot to like -- nice variety of enemy characters, a nice variety of physical environments, good animations, enemy controllers work well, the directional fire worked well for different challenges, and I like how your music seems to have different variations on a theme. I also enjoyed the world-building art (multi-screen setups, flowing sewage, etc.), and the sound effects are great, too. Nice! I wasn't totally sure if I covered everything in the game, but after beating the big rat and using grenades to open doors, I ended up in one empty dead-end area I couldn't get out of, and also explored the multi-floor elevator area where there was a savepoint and the other 5 or so floors were empty, so I figured I was reaching the "in progress" areas.
Some feedback that I hope is helpful: (1) the jump mechanics felt a little difficult to maneuver and I don't think I ever totally got comfortable. When I push left or right while in air, it seems like it gives me a pre-determined amount of horizontal movement, as opposed to allowing me to continuously control my character's lateral movement by holding down or letting off the horizontal keys. There was also occasionally a bit of a sliding effect when I'd land that I had trouble controlling -- not sure what makes it happen or not. (2). I would set up the keys meant to be used frequently (jump, shoot, dash, grenade?) along a single line -- e.g., the common C-X-Z-Shift grouping. Because the constantly-used control and space (shoot/jump) keys are so far away from the dash, punch and grenade keys, I played this game without using dash or punch almost at all, and used grenades only to open doors. I would also echo what others have said, which is that I'd love to see up/down used to initiate ladder climbing rather than a separate key -- even if that means you can't shoot downward while standing on a ladder. Finally, Control+arrow is a preset shortcut on my computer that moves the game off-screen and shows my desktop (I didn't know that until now), so I'd avoid using Control as one of the gameplay keys. (3) I think "coyote time" would be a good addition.
Sorry to write so much, but I see you put a lot of work into this and I played it a bunch, so I wanted to provide meaningful feedback. Nice work!!