Much appreciated!
Addressing some issues though; level 3 is the only one with no boss fight so in order to make the game enjoyable we had to include multiple enemies because "chaos" is one of the key aspects of the game, so the actual fps problem stays for the while because of unity not handling the amount of enemies but it was a compromise to make the level not empty. A better execution would've been finding a middle ground.
The second and the final boss (after level 3) fire ranged attacks (third having it much more accurate and more frequent).