Tip 1: As with all tower defence games, carefully consider where you place your towers. Find spots where your defences can attack aliens more than once such as switchbacks or corners.

Tip 2: Sentinel orbital weapons like the homing missiles and ion bomb are extremely powerful and great for saving you in a pinch; however, you can only use them by generating enough energy, which accumulates slowly during each wave.

Tip 3: Upgrades are vital to success. Balance the purchase of new towers with credits spent on upgrading your existing defences. Often upgrades more than double a unit's attack power.

Tip 4: Don't spend credits purchasing a slot until you have a tower or ability to fill it.

Tip 5: A fast-forward button lets you speed up the time between waves since you're unable to control the start of each wave.