17: Fort Gib

There are two routes here with considerable distances between each tower spots. However, you’ll have lots of starting cash. At the start of the battle, concentrate your defenses near the HQ. You’ll deal with fast ground enemies and airborne targets most of the time so have at least one AA battery near the base and a deathbeamer beside the base. Once you’ve earned enough and upgraded your core tower defenses, leave one soldier to defend the base, preferably someone that has an AoE attack/ crowd control ability like the Assault, Saboteur or Scientist to deal with anything that gets past your defenses.

Move your other two soldiers to the middle of the map where you can install a healthgun. I’ve used an Assault unit to defend my base, while a Rocketeer and Bombardier went to the frontlines and kept alive by the healthgun. Fully upgraded healthguns can heal your soldiers very fast, enabling them to stand in the middle of the enemy swarm and still survive. There are lots of heavily armored enemies here so deploying your firepower powerhouses will help a lot in winning this battle.