The game is not bad, there are various enemies, but the gameplay seems to be unfinished, the animations are strange, the collision boxes seem to be too big, both the player and the enemies.
Even off-screen Snipers shoot the player, as well as spawning enemies endlessly, all of which leaves the game quite unfair.
It seems that it is using very heavy effects of post processing, there is no drop of frames in the game, however my PC heats up a lot, as it is in pixel art and does not have so many light effects "at least I did not see many in the 3 phases of the game" , there is no need to use so many resources.
To your pause screen not for unity timeScale, everything in the game keeps on happening.
Watch this video that teaches in a very practical and simple way how to make a pause screen.
I love your art style, congratulations.