If not the max possible damage, then find and equip "Greek Fire," an oil throwing weapon(50-200 damage), move around the map until you find a large group of enemies, and throw at the group for a splash damage(damage is at least 50 for each enemy, easy 500 total damage). Hope this helps for the medium badge.
The medium badge doesn't actually need the damage in combat, but instead seems to be based on your max possible damage. For example, I equiped "Mysterious Hunter Bow of Death" and the stats were 5-15, may increase damage by 0-1000 points, and when I exited the inventory, I got the badge with the score saying 1070. I'm not sure, but find and equip a weapon that has a possible damage over 300 to get the badge.
for the boar boss, stand at the very top/bottom of the screen and w8 until the rumbling starts. when the screen starts shaking, move up/down, depending on where u stood b4. when he throws the spear, pick it up and throw back at him to stun him. then, attack him and repeat
if you saved your game and tried to play it again on a different day, you might not be able to continue. when that happens, see if you clicked load b4 clicking play
for the boss, save ur bullets and dodge the bullets un til it does the twirl spin thing. stay under the boss until it stops and get out. shoot it when it slams on the ground. repeat the process.
@pigbag try using shotgun on the big zombies and the uzi on the small ones. when ur using the shotgun and u have to reload, switch to uzi so u can keep on shooting, then when the shotgun is done reloading, switch back. i hope this helps u get past lvl 3 :)
@Darthkac do u train ur strength or life, cuz if u don't, start training. If u don't want to use ur training points, then save up ur money, go to the healer, and buy the strength and life ups. That's wat u need to do if u want to beat the guardian, if u don't know already. I'm sorry if i offended u tho
keep throwing the peoplez at the nest and hope tat they go in
when the cars come, use them as bombs/shields
when the levels turn hard, just use the cars/trucks/tanks as bombs
u dont need to throw the people anymore-the cars take care of that
for helicopter, just throw a car at it to make it explode
hope this helped :)