Took me forever!
I usually do not like tower def games much since they are so hard to beat, but this one allows leveling up, which is great. I spent several days maxing out my level to make getting a brilliant on level 15 possible (stupid ninjas!) I developed a great strategy for dealing with ninjas, and that is to place burning temples near the entrance to instantly hit them and deal major damage. The AOE hits invisible ones too. Unfortunately this is hard on the last level, so I placed my Burning Temples around the gems and filled the map with crypts. These damaged the ninjas quickly enough so that they were no longer invisible by the time they go to the gems and BAM, AOE goes out and kills all of them. Unfortunately, getting those 3 Burning Temples set up and leveling them took some major luck since on the last level the enemies can all spawn on the same side and screw you royally. This is not an issue unless you want brilliant, however, so I won't dock any point for that.
One glitch I noticed: Sometimes they pick up a gem that has warped back as if it never warped back at all. This is a bit annoying but not really game breaking since you get EXP even if you lose, which is great.