Even with all these brains on hand, there's always one big dummy. There were hundreds of zombies diligently chasing down the last few victims. Then there was one zombie that couldn't figure out how to get out from behind one of the cattle fences. Poor thing wasn't even on the inside.
Have all autobuyers enabled up to the prestige layer 4 screen. Can afford upgrades in prestige layer 3. When the team dies, this message gets spammed to the log: "Auto-prestige triggered by your Prestige Layer 3 Armor auto-buyer! (x6 > x6)" Nothing is actually bought, as foreshadowed by "(x6 > x6)", and yet this prevents the lower autobuyers from doing their jobs, effectively bringing progress to a standstill.
Sometimes when the team dies, it's not auto-prestiging even though it could buy things. Sometimes hanging when the team dies and it should be auto-prestiging. On the latest refresh, I now have prestige points that my autobuyers didn't spend. I thought the game was running pretty well before I refreshed today...
No amount of strategy can get you through some of these levels. If the pieces don't fall your way, then forget it. Also, I clicked the center of a + arrangement just now, and no spell was cast. Ofc I'll never be able to prove it...
By the time I hit level 45 and could get the Mega Beam skill, my equipped weapons were better. I activated the skill, and immediately wished I hadn't. (That's without using CluelessWonder's trick.)
The "super" powers that can be picked up during a stage often turn out weaker than what I was using. Not to mention what all the top-ranked comments say...
Getting the hard badge definitely seems to be related to luck rather than difficulty---can you get a yellow madness near the beginning, and then enough purple powers?
:P