For Hard Badge, go for a glass cannon approach. In upgrades. max out Move Speed, Reload Speed, and Vision. In weapons, max out Projectiles, Damage, and Fire Rate. You'll be spitting out plenty of lead to take out anything close to you, and you'll have enough run speed to slow down the approach of fast zombies while you are reloading. You'll also have plenty of vision to see where enemies are. Lastly, In survival, you will be completely surrounded by zombies on all sides. Pick a direction, and blast a hole into it, then escape the circle, making the zombies chase you in a singular line as you pump lead into them.
Could you please add a reset/restart button, so we don't have to reload the page? That functionality is kind of basic to any video game, where it's possible to lose the game. That's pretty much game-making 101.
 "Hat Wizard 2"){kind=icon}
 "Otter Life"){kind=icon}
 "Ring Pass Not"){kind=icon}
 "Kids Vs. Santa"){kind=icon}
 "Destroy the Earth"){kind=icon}
 "Incremancer"){kind=icon}
 "Not Enough Money"){kind=icon}
 "Peasant War Experimental"){kind=icon}
 "Reaper of the Undead"){kind=icon}
 "Turbo Town"){kind=icon}
 "Yule - A God Birth"){kind=icon}
 "Immuno"){kind=icon}
 "Neon Wars"){kind=icon}
 "Llama's Chicken Farm"){kind=icon}
 "More Bloons"){kind=icon}
 "Bloons Super Monkey 2"){kind=icon}
 "The Zombie Food Truck"){kind=icon}
 "Squid Ink"){kind=icon}
 "Hedgehog Launch 2"){kind=icon}
You must play the Judas Priest song while you do it for extra credit