там в советах написано это
Legacy Build for Older CPUs
A legacy build is now available for older CPUs: eg
AMD Phenom
Intel Core 2
To enable the legacy build:
Open your Steam library
Right click Planetary Annihilation: TITANS then select Properties
Select the BETAS tab
Select legacy - Default for older CPUs
Click the CLOSE button and Steam will download
https://planetaryannihilation.com/guides/planetary-annihilation-public-test-environments-pte/попробуй может запустится