Hey! Nice to see you around here again from the last gmtk! We noticed too that the difficulty curve seems unnusual because it starts "hard" then it progresses to be easy again when suddenly it becomes even harder next wave, so much so that actually I had to edit my score on leaderboard just to see how it shows the megabrain text in game but forgot to fix it again, so technically you are the first to get the megabrain rank, nice job!
Good to see you again, maybe we'll meet again next year! gl!