New version 0.9.2

Another batch of updates! These fixed should hopefully address some of the balance issues as well as polishing and adding to the game. Have fun!

• added difficulty settings
• added new room: vampiric cult
• added new enemy: knight
• added gold popup when mining gold
• added visiual indicator when a new quest is given
• added three new quests
• added gold rewards for completing quests
• added designed enemy waves
• increased mystic healing power from 1 to 4 hp
• reduced spawn time between heroes (from same portal)
• changed scroll and runestone spawn positions
• changed color ramp on flame breath attack
• fixed some ui interactions not being available after game ended
• fixed buttons overlapping in some cases
• fixed spikes using wrong sprites when untriggered
• fixed odd room contents if placed near walls
• fixed graveyards crashing the game when enemies died