Onslaught Tower Defence: The attackers are coming! Theyre trying to fight their way into Area 51 and its up to you to build the defences and stop them getting in! Theres a cash bounty on the head of each attacker, and each wave is tougher than the last. Spend your winnings on upgrades to your defences to keep the attackers at bay. The hitpoints of the attackers increase with 120%, so be sure to upgrade your towers!