Add modes, I would also recommend adding a title screen in case the player wants to change modes. Here are some things I have:
WELCOME TO DUALFORCE IDLE, DO YOU WANT TO:
Start new game
Continue
Change mode
Modes: Sandbox: Have infinite money, Spawn monsters, and Infinite rebirth points. Master Mode: Items are much more expensive, monster upgrades are cheaper but gives monsters more strength than usual, monsters give less rewards.
