Tips and Tricks

1: Grind tech points in the Beginner levels (prologues) You'll get around 1,600 tech points for completing the mission and destroying all research waves. The difference for clearing higher difficulty maps isn't that large so you might as well take it easy. You can even leave your tablet running once you've established LV3 towers near the portal(s).

2. Prioritize leveling up the Comm Tower and Holding Towers. The Comm Tower's rank 1 upgrade will increase its range and upgrade speed of towers within its range. The Rank 2 upgrade will give you bonus cash for every enemy defeated within its range.

3. The Holding Tower in the other hand is an invaluable asset to your defensive arsenal. It can greatly slow down any air or ground target, including bosses. Its Rank 1 upgrades lowers its upgrade cost whenever an enemy its holding is defeated. A level 5 rank 1 upgrade will lessen a Holding Tower's upgrade cost by 10 per enemy killed. This applies even if the holding tower just barely "touched" the enemy and was killed immediately. You can also further enhance the Holding Tower's slowing effect by leveling up its Rank 2 upgrade.

4. When defending against airborne targets, don't rely on Skywatch Towers alone. Place a Holding Tower or two beside it, as well Rocket Towers and Reaping Towers nearby. If its outside your main Comms Tower, build one nearby as well. If your space is limited, you may want to build at least two Skywatch towers and consider upgrading your existing Rocket, Holding or Reaping Towers.

5. The game is nice enough to display the airborne enemies' projected flight path. If it is too far from the ground exit, you can place AA (anti-air) defenses near the edge of the map where they'll be arriving. Your towers will be able to shoot them down before they even enter the battlefield.

6. Upgrade your towers as early as possible. It will be unwise to make too many towers and spread your defenses if they aren't strong enough to kill the invaders. Attempt the harder difficulties only after buying considerable upgrades for your towers. Default towers won't help that much in stopping the invaders.

7. Tower placement is important. Take note of a tower's range to effectively put in into position. You don't want to place your Rocket Tower along the main path while your Mortar tower is sitting behind. Being able to effectively gauge your tower's reach will make things easier for you in the long run, especially if you need some concentrated firepower on a large Titan or enemy.

8. Spend your tech points regularly. Hoarding your tech points doesn't have any particular advantage so after earning enough to buy an upgrade or two, visit the in-game store and spend them.

9. The other Commander Abilities are not really that necessary. You can finish the game with just the default bomb and Deep Freeze abilities. It will be better to spend your hard-earned tech points to tower upgrades.

10. For maps with two portals, divert the enemy's path so that they will converge in a single path. Though it may be a good idea to place the bulk of your defenses here so that you can hit them all at the same time, it's still a better idea to take out or heavily damage enemies as soon as they exit out of the portal. Finally, for maps with two exits, you can completely block off one of the exits and force the enemies to march to the farthest exit.