Like almost all Renpy games Windows 7 64-Bit or any higher Windows with 64-Bit.
As for HHG: Windows 7 64-Bit or higher. (other Renpy games here on itch.io might be 32-bit, but those compatible with Windows XP are extemely rare today.) It should work even with a very slow CPU/GPU/RAM.
But you absolutely have to pay attention to the known bug when it comes to rendering: When you play for the first time on PC, press SHIFT+G and change renderer to "ANGLE". Otherwise if would crash at a certain point (... Evie in the park)! Lots of HHG gamers and almost all PCs suffer from that issue. Restart the game once and the renderer is set correctly now to prevent that bug.