Oh, and Duungraf, you don't need to mouse over restart. The restart hotkey for this game is the SPACEBAR. For all of those who keep complaining about R not restarting.
For Moon Castle. You will need 1 of each and position them in the following order: SoulSeeker, EntropyAlien, Chakra, ScarFace, and Corpse King. Equip 1 best Attack Gem and 2 best Health Gem to Chakra as this is your primary frontline attacker. Equip remaining Attack Gems on SoulSeeker while the remaining Health Gems to ScarFace followed by Corpse King. Make sure all of them are max upgraded before starting the battle.