Cascade

Doesn't work.The first skymaster gets through before you can upgrade missile tower 2nd time.

Strategies
Towers used: 2x Missile, 2x Stun Gun, 2x Boost

Time: 11:10.6

Build Order: 1 Missile, Upgrade Missile, 1 Boost, 1 Stun Gun, Upgrade Missile, Upgrade Stun Gun, 1 Boost, 1 Stun Gun, 1 Missile, continue to upgrade all 6 towers.



Credit to Sheiva Y.

Towers used: 2x Stun Gun, 2x Missile, 3x Boost

Time: 9:11.6



Credit to Chris B.

Towers used: 2x Flak 1x Boost 2x Mortar

Credit to MK