Can beat this at level 60 by just using dual gem mastery and only using dual gems, saves a tonne of skill points. Make sure you max forge and replenish too asap. For those who make it to the last level, the game ends immediately after dropping the 7th bomb so just store 7 grade 7 gems in towers and use them all at once.
I like this game, decent potential, I think it just needs a few more things, mainly statistics (I know I personally love to know exactly how time intervals and worker power etc change with each upgrade). Just a bit more information regarding the reset as well, it's not obvious at first, and not having a base multiplier means you can't be quite sure how much of a difference a reset will make
 "GemCraft Labyrinth"){kind=icon}
 "GemCraft chapter 0"){kind=icon}
 "Idle GameDev"){kind=icon}
 "Dangerous adventure"){kind=icon}
 "Cursed Treasure 2"){kind=icon}
 "Paladog"){kind=icon}
 "Innkeeper"){kind=icon}
 "Pel"){kind=icon}
 "Take Something Literally"){kind=icon}