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Helicopters to destroy: 6 Bomber Helis
4 respawning Robots

[edit] Tactics

Attack the helis with any weapon apart from the soundwave, black hole generator or atom bomb, they should be kept for the final levels, but use them if you get into trouble. To dodge the bomb attack, hyperjump and use time break and you sold not take any damage, after you dodge it, follow the helicopter for a lot of free shots while it bombs the ground. If the helis are not using the bomb attack, you can usually just run from right to left without taking any damage.