I like the idea of using a "scaling gun" to clear out a path for the character. I like that the level contains multiple paths and there are multiple ways to clear parts of the level, The game is difficult, and unfortunately I think it is also very frustrating.
My suggestions to improve the game:
1) Add an option to reload ammo immediately. There are parts of the level where you need multiple ammo to clear at once. While reloading immediately is possible by using up remaining ammo, it takes some time to do so, which players may not have at all times. Allowing immediate reloading thus allows players to be more ready at all times.
2) Split the level into multiple smaller levels. It is very frustrating to play a long level with no checkpoints, along with the sudden dropping of objects near the end which I did not expect. With smaller levels, the frustration from having no checkpoints is significantly reduced, as well as allowing the possibility of introducing gimmicks (like the aforementioned object dropping).
3) Larger field of vision. I feel like with the current field of vision, players need to plan out the moves faster, which can worsen the player's aim, especially near the end. Having larger field of vision give players more time to plan and thus make the game less frustrating to play.