[Zomboy]

So, You're saying you're running the game on an Integrated GPU. There have been many issues when it comes to running the game on an Intel Graphics. Since its not a reliable gaming GPU although you're using it to run a low -end game like San Andreas.
I'd recommend you to switch to a entry level gaming GPU (Nvidia or AMD).
Or, If you already have a gaming GPU installed switch the game to that processor and try again.
Also if you'tr not able to buy a new GPU you can try updating the Graphic card and try again.