Sandstone

Steal a box from a Zone Guardian, get it back to the Safe Zone, unbox a PC, and place that PC in your pen. The pen turns placed PCs into money. Train Speed on the treadmill so later zones are escapable.

The Roblox description says 30 zones, and each one has its own PCs. Recommended Speed figures are published for Grass (5), Forest (1.5K), Mushroom (67.5K), and Desert (650K). The other zone names and gates are not in one official list.

Trails multiply Speed gained on the treadmill and add a visual trail. Off the treadmill their gameplay effect is described as minimal, so they do not replace the Speed stat you need for a zone gate.

Every hatching box and placed PC uses a pen slot. A full pen blocks the next placement until you upgrade the pen at the base board or remove something. One reported message is Pen full (13/13)! Upgrade it at the board.