ROFL. Here are some more "lesser known secrets" of Gemcraft: 1. If you combine 3 gems of the same color, you unlock its hidden level. 2. If you combine all the colors together, you unlock the special Rainbow Gem secret level. 3. If you beat the game before level 25, you unlock nightmare mode. 4. If you get glowing frame on every level, you unlock glowing gems. 5. If you get and upgrade all the skills, you unlock sandbox mode. 6. If you get all the amulets, you unlock the secret amulets window. 7. If you get all the secret amulets, you get the awesome "Anti-Gemcraft" mode, where you create the waves of creeps for each level. I'll post a walkthrough for that mode later on today.
Thanks for the extra hints. I will try them out. I've made it to level 23, but I can't beat the glowing frame hidden level (green gem), or the first epic level.
For some reason I can't seem to get the balance right between building up my defenses and having the right amount of mana to withstand being overrun.