14: Frozen Fissue

Campaign

Waves: 5

Starting Energy: 1800

Lives: 20

You should have enough money to fully build a specialized tower. The laser tower's Quad-Ray is perfect for handling up to four enemies at once. Prioritize upgrading your nearby towers and call in reinforcements to help hold the bottleneck position if ever. The new enemies you'll encounter here are vampires, which siphon health from your troops and Artic Rocketeers, which are basically more powerful version of the rocketeer. Vampires are also shielded so laser towers are great against them. The waves are pretty much manageable, as long as you keep upgrading them. The last wave will also include wasps and icers so make sure you immediately clear the ice from your frozen towers to shoot the flying pests down.

Veteran

Waves: 6

Starting Energy: 1750

Lives: 1

You're only allowed to build MG towers and laser towers. You should have enough money to fully build a specialized tower. Prioritize upgrading your nearby towers and call in reinforcements to hold the bottleneck position. Carefully make new towers and upgrade them to at least LV2, especially the MG towers. There are a lot of enemies per wave, enough for you to build more towers and even fully upgrade them to their specialized forms and their corresponding effect boosts. Be careful of the fifth wave where wasps will arrive; make sure you're ready to zap them with your Tesla Tower in case your towers weren't able to shoot them down. Finally, the last wave will consist of more vampires so keep your troops away from the bottleneck as much as possible and let your towers deal with these life-suckers.

Spec Ops

Waves: 1

Starting Energy: 1750

Lives: 1

Build a specialized tower in the bottleneck, preferably in the spot near the bridge. Next, place a rocket tower near the bottleneck and start placing at assorted towers in the other slots. Make sure to have at least backup towers since wasps will be joining the wave early so you need something that will shoot them down if they get past your defenses. Once you're able to deflect the wasps, you just need to worry about the icers and vampires.