keybinds

• use z to reset current layer
• use x to buy all available upgrades once
• use Shift+X for both above
• hold them to repeat faster
• use Shift+[layer key] to switch to it

stars

• stars are shown for upgrades, milestones and challenges
• silver if there are hidden ones, golden if there are none
• full if maxed, empty if not
• red when inside challenge, full red if can complete it