Finally had the hard badge. But I hated my life at times I pressed R on checkpoint flags. Double tapping R for level reset is a lie. You should change level reset to another key, so less people swear at you in the future mate :)
There is a bug with warrior's live button. when you click live it doesnt return back to normal, just keeps sliding crouched and leaves game then. it's not hard to notice it...
Also it would be good to start with all containers full of health after upgrading them.
Now i got the trick of survival, it gets you bored with a slow wave frequency (kind of one wave in every millennium). When you are over 400 coins... BOOM!!!
You're in luck because there IS an iOS version (as well as other mobile devices) and there are even 20 more levels in that version! Check the link in the game description.
 "Cube Escape: The Cave")
 "Jumphobia")
 "Smokin Barrels 2")
 "Crystal Story II")
 "Strand"){kind=icon}
 "Feudalism III")
 "Endless Evil")
 "One Step Back")
 "Arkandian Explorer")
 "Hordes and Lords")
 "Legacy of a Thousand Suns")
 "Legacy of Heroes"){kind=icon}
 "Dead Metal")
 "Music Catch")
 "Coins"){kind=icon}
 "3 Slices")
 "LethalRPGDestiny 2: Conquest"){kind=icon}
 "Lab of the Dead")
 "Katwalk"){kind=icon}
You're in luck because there IS an iOS version (as well as other mobile devices) and there are even 20 more levels in that version! Check the link in the game description.