This game is really, really easy even without an overpowered build. Note that some skills (i.e. Brawler) are utterly worthless against non-debuffed armor enemies.
Waizer (Tank Mutant): BIOFIELD, PARALYZE, BIOFIELD, DECAY, BIOFIELD, DECAY, BIOFIELD, DEBILITATE will destroy him even without a good weapon! You can also oneshot him with DISINTEGRATION if you DECAY/DEBILITATE his stats down enough or FORCE/IMPROVE/DEMON FORM yourself over his stats.
Skip the Biofields if you have a Potion of Battle Fury.
Also, you can clear hordes of enemies spamming Sacrifice and using allies as meatshields.
Please let us respec, add more weapons and maybe a good story. Way too many random battles, but fun game nonetheless.
The trick to this game is:
1. Shut down hospitals in mostly immunized (>90%) states
2. Form a contingency plan and inoculate the *neighbors* of highly infected states. Then immunize states with airports/harbors and no hospitals, then states bordering Canada/Mexico, then the most populous states.
3. Curfew+Vax+Mil Support on states with many infected AND healthy
4. Border control is only useful on states with very few borders (ie Florida) that get the infection first.
Damn, that was great. It really proves that level design can make a game as simple as this good. For everyone having trouble getting the badge, reload the game. (Progress is saved)