To anyone doing BOTD I recommend doing the ones for the next two days while this one is idling in the background, because those ones are particularly hard.
To anyone else still having trouble with the medium badge, click on the question mark to see detailed information about the game. Most important is the "summary" section, there are some important tips in there. Also try asking for help in the konkr.io discord server.
After winning a level, I like to surround the remaining enemies with towers and force them to fight to the death like hunger games. Anyone else do this? ...anyone?
(Spoiler Alert) Finally got "brilliant" rating on all levels! The boss ninjas made it harder than it should. All boss ninjas die to 5 meteor hits except for the one at level 14. How I dealt with it was by maxing out freeze and spamming crypts. Use the left crypt upgrade which has better fire rate. Before the ninja boss wave, sell all dens/temples that can proc ninja invis before the crypts do. A crypt charge should be the first to hit the ninja. Since freeze only has a 25% chance of proccing, this strat will fail 75% of the time. You may need more than a few tries. But trust me when I say it works.