Nice work. I really like this. The character is well animated and feels good to control. Run speed, acceleration, jump height, etc... all feel good and polished. That "starting run" animation adds a lot of character, even though it's short. I like how you have that without having a delay to the movement. The "float time" in the air is cool, I think it makes your jump mechanics stand out a bit. Kind of a short Peach float, before you start falling. The dash feels good, the shape of the motion is useful and interesting. Back-dash when you're not holding a button is a good idea. Great work on the camera, it feels smooth and natural. I think you're on track to have a very nice platformer.
A few crits/suggestions though. When you release jump, you can divide the y velocity by something between 2 and 4. This will make it smoothly stop, instead of setting the y velocity to 0 and making it instantly stop. Infinite range on the gun reduces the strategy of most encounters. Just stay as far away as possible and shoot. Shorter range would force players to get in closer to enemies, risking more. This would also set you up for a nice upgrade later.
The stamina bars are really hard to make work. In my game, I had a system like that for quite a while. Every attack/roll would use up some stamina. But no matter what I tried, it never really added anything to the game. It just seemed to the players to randomly make things stop working. Even once they figured it out, it never felt natural or fun in any way. And the same problem is in your game. There is nothing fun about not being able to shoot or dodge. It's just frustrating. All you can do, as far as I can tell, is sit around and wait for it to recharge. If you watch people play, that is usually a hard stop for them. If you can find a way to make this work, good on you. I couldn't and I'm glad to have taken it out of my game. In it's place is a positive system, where you're rewarded with more powerful attacks if you can build up energy. Instead of a negative system, where you're punished for doing the main things you're supposed to be doing (attacking and dodging).
If you're like me at all, you were looking at Dark Souls to see how its stamina system worked. The stamina in that game was really the backbone of the entire experience. But what I found was that the slower timing of confrontations, and the way they used space was why it worked at all. It forced you to pace yourself, and balance your attacks and defenses. Then, you could run away/run around if you used too much stamina, and that act itself was fun. In 3D space, you have to watch the aggressor, and try to avoid them while you're vulnerable. That's all much much harder in a 2D side view game.