The problem is that the pistol is op, you can just 1 shoot most of the enemys ...
you can use shotgun jumping to make shotgun more usefull and make it have more damage that is short ranged also for the assault rifle make it have higher fire rate or not reload that would balance it out i think... but wait.. the enemies would get rekt.. make enemies be faster mostly the bomb make them be able to regen mostly the tank thing and ADD BHOPPING