Never managed to get a cascade rocket launcher, but the Tripe edge grenade launcher works pretty darn well for everything. With a thor lightning gun, just sit in a corner and it shoots everything for you. Haha.
first time playing, got everything by the 27th game. lol. heres a trick for surviving 3 mins, fly your leader all the way out of the screen, you wont get hit. but after awhile, when you get upgrades you'll be able to survive 3 mins anyway.
 "A Bonte Escape"){kind=icon}
 "Elements"){kind=icon}
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 "Remnants of Skystone"){kind=icon}
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 "Valthirian Arc"){kind=icon}
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 "Alice is Dead - Ep 2"){kind=icon}
 "Endless Migration"){kind=icon}