Gigapocalypse

You need to see the Zap/shoot a flying Hawkman 5 times, across separate runs. He can be found on the beginning (usually the first 60 seconds) of Wild West 1. He will appear in the upper middle area of the sky. I shot him a bunch of times until he flew off. Once he disappears, hit cn_start, select upgrade to take you back to the menu, and do another run. His appearance is RNG-dependent, so if he doesn’t show up in the first 60 seconds, quit out and start another run. Took me about 10 minutes to unlock after about 15 or so tries.