A. 1. Explore all upgrade options: Check the upgrade menu thoroughly to see if there are any hidden engine options or upgrades that you may have missed. Sometimes, certain engines can be unlocked through specific achievements or challenges. 2. Participate in events: Engage in special events or challenges that may offer unique engines as rewards. This can increase the variety of engines available to you.

B. 3. Check for community mods: While not contacting developers, you can explore community forums for any mods or custom content that may introduce new engine options.