Malwols , u can play tricks when changing range , like if u start close with onimaru , then u press close, or pass when at far , then ur opponent will press far to stay away from you. Its all about energy control
Ya balance is an issue here , cuz once you get to sniper rifle, you win . and i would suggest that u can add sell tower, cancel buttons, restartlevel , and maybe some small boss between levels, and upgrades for towers and maybe mines for emergency
for ppl having difficulty passing the factory , Use the upgrade revolver for the ghost and those crazy miner , and use the platform wisely, you can see that when the massive crowd under except ghost follow your movement. so when ur on top, u can kneel at the edge and throw a couple grenades down. and use flamethrower to keep the bear and the fattie back . auto shotgun is best for those nasty lil jumpy thingys.... save the "0" and minigun for the boss ,