17: Oasis of Ash

Campaign

Waves: 9

Starting Energy: 1400

Lives: 20

In this battle, you'll have to deal with three new enemies: the Jolt, a droid that can disable nearby towers temporarily, the Enforcer that buffs their allies' health and damage, and the Behemoth, a stronger version of the Juggernaut. The jolt are more annoying than icers since you can't do anything to lessen the downtime of your affected towers. Concentrate your forces on the bottleneck and fully upgrade a Quad Beam tower. Build two infantry towers to guard both checkpoints, then place a rocket and MG tower on the other slots near the bottleneck as well. Upgrade the MG to LV2 then start the battle. Once you have enough energy, upgrade the rocket tower then continue building energy so you can upgrade your MG to LV3. When you have enough energy, clear the rubble on the blocked slot and build a tower there, preferably an MG tower that you can turn to a Railgun. From hereon, you can upgrade your infantry to LV3 and start building other towers.

The idea is basically establishing a solid roadblock so that you can easily hit more enemies at once with an airstrike or tesla charge while they're being funneled by your forces. When the behemoths appear, make sure to tag them so your towers can focus fire on them immediately. They can deploy shields when their HP is low and will charge past your troops if not killed quickly.

Veteran

Waves: 6

Starting Energy: 1250

Lives: 1

In this mission, you can only use Infantry and MG towers. Build three infantry towers in the bottleneck and place MG towers on the nearby slots. Don't occupy all slots but make sure to upgrade them at least to LV2. Start the battle and earn enough energy to upgrade your infantry towers and MG towers nearby. If you have the MG tower's Mini-gun specialization unlocked, change to that. Better yet, if you have the Vanguard upgrade for your infantry tower, switch to that too. Be careful about the juggernauts; even with fully upgraded infantry or MG towers won't be able to kill it fast enough. Keep your finger on the tesla tower to zap any Juggernaut that may slip past your blockade. Use your airstrike as well, especially on the last wave where Juggernauts are accompanied by Enforcers.

Spec Ops

Waves: 1

Starting Energy: 1450

Lives: 1

All tower spots are clear so you can establish your defenses more effectively. Concentrate your defenses in the bottleneck and at least build a Quad Beam tower again. Support it with a Rocket tower, two infantry towers and other two towers of your choice. Don't hesitate to use your airstrike to soften up or destroy the Behemoths. Keep upgrading your towers and further enhancing their firepower and bonus effects.