Boss Ninjas - whup up with a maxed out snow tower on entry, and then use fire towers closer to the treasure. In the meantime, smack em with 4 meteor strikes. Also helps if you have your powerups maxed on freeze and fear as that slows them down!

I only got all brilliants at level 45 (the last four took a while)

Haven't had the no spell thing - sometimes I am hovering there waiting for my mana to reach the right level, but no glitches like that