This game wasn't difficult at all. Don't see why people had difficulty, even with the lag and overpowered opponents. Hint: Destroying a tank is far better than deploying one.
Assault teams and support fire can handle tanks with ease and it is by far more efficient to deploy machine gunners en masse than snipers.
Another Protip: Points are easiest in the challenge mode as you'll only have 3 games to worry about. Green is the easiest since your time on WASD keys on Kongregate will pay off when you use your peripheral vision. I think Pink is the hardest since the more time passes the more it seems like Flappy Bird.
Pro Tip: Do not worry about the score you get at all. Once you hit your "zone" and have a rhythm, the medium badge will come to you naturally. It'll be easier when you get thegames you're better at, so be patient and wait until RNJesus looks your way. Now about that hard badge... good luck! XD
To those who need a heal function, you obviously do not understand the concept of the game. This game deals with risk taking and money management as well as combat. If there were a heal function, the game would be pointless. Stop whining and learn to play the game the way it's meant to be played.
Use the healing hero, and never let it go into battle after stage 4. Just spam the freezing spell and healing tower. When facing the boss use the attack and defence booster skills.
My setup: Vampire warrior, Centaur, Archer, Paladin, Amazon and Minotaur
It's a good idea to be a bowmaster with a dwarf race. At the first possible opportunity get the multishot skill. Then get the point blank skill. With MP and HP steal this makes you impossible to kill unless you get 1 hit KOed, which is unlikely, even if you are surrounded by 8 melee and 16 ranged units.