Hello, first of all I would like to say that I really enjoyed playing your game. I personally love it, but I have seen some details that could make it more intuitive and fun.
I would like to say that I played with a PS4 controller, so my feedback on the control buttons will relate to that controller.
On the PS4, the button to accept/interact in menus is the square, which feels a bit awkward. Usually games use the X button on the PS to accept (the A on the X-Box), so all games speak a common language and it's easier to play your game.
The buttons for diagonal aiming are also weird (L1 and L2). Personally, I would prefer AM2R's. The ability to aim diagonally without having to press a button, but also having one for it just in case you want to aim diagonally while not moving. I also think the buttons chosen for this are a bit awkward, as they are both for the left hand. It would be good if you arranged them at the same height like in Super Metroid, one for the right hand and the other for the left, like in Fortnite. Triggers are usually seen as pairs, so if one is aiming up, the other is aiming down. Another solution would be, like in Metroid Fusion, to have a trigger for setting the diagonal aiming mode and then using the joystick to set whether you aim up or down.
I know you can change this in the settings, but it would be nice to have this from the start.
I would like to talk to you about the map, especially the control schemes. Since the camera is inverted, I would include an option to move it without the inverted schemes, just that.
I would make the HUD a little bigger so that unsuspecting players can perceive it better.
The splitter beam throws three beams, and in games like Metroid, one of the three beams is near Samus legs, so she does not have to switch between diagonal aiming and non-diagonal aiming. As this beam is usually found near the end, it helps to destroy everything easily and get through the different rooms quickly. In doing so, it vaporises any enemy at Samu's feet so that she does not lose momentum, because by the time the player gets this upgrade in Metroid, they have already shown that they can easily take out these enemies, so the game makes it even easier and empowers the player.
The last point I wanted to give you feedback on is the collisions. Be more permissive, players will not care if a collision is one pixel bigger or smaller. So make the hitbox a little bigger so it's easier to hit enemies, players will not notice that the hitbox is bigger, and that makes the whole experience more satisfying.
I will be following the development and once it's complete I will write a full review of your game. I love it and have seen these things, so I wanted to give you a heads up. I hope the development goes well ;)