Currently, SimCity: Complete Edition players on MacOS 12 (Monterey) may find the game only opens in the top left corner of their screen, and the rest of the game is cut-off. We apologize for any inconvenience this causes, and we're currently investigating this bug.
While we're looking into this issue, a quick workaround is to press control + F, which should toggle your game between fullscreen and windowed mode. Pressing control + F twice will get your game back to fully visible in fullscreen.
If your SimCity: Complete Edition is still cut off after using this workaround, or if you have any questions, please submit a ticket to us. And if you'd like to be alerted to when this issue is resolved, click the "Follow" button at the top of this article and you will be notified when any changes are made.