if you unlock the demons, start a campaign with them, but then start a campaign with a different race you lose the demons and have to beat the game to get them again,
all you have to do to beat the boss really easily is to have the red and green key, then get past the boss without killing him, get the upgrade then kill him
when my nuke combo failed to insta kill i built more of them. currently i am on wave 367 without losing a single life. nukes are the best turrets, spam them with range and fire rate by them.
1916 is glitched. for me it will slide the camera very far away from my plane and if i try to move it it will go back to the same spot. ive even tried quiting and restaring the battle and the same thing will happen
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