There is a settings menu if you need to change graphics settings/ performance settings! Need further optimization? Check out the config.ini in the game folder. 

This is still early in development so there will be a few bugs. I believe that most of them are already known, so here is a short list of the ones I have found and not addressed as of yet:

• Exiting the vehicle at the exact moment of reversing/accelerating may cause the vehicle to never slow down and thus drives away without you
• Looking out of windows causes some texture pop in/out. I'm not sure what causes this one, it might be an engine limitation with handling transparency, but it's here and will be addressed at some point.
• Textures can load in improperly or sometimes lose their opacity after compilation, this is something I am currently trying to address as well, so forgive me for any missing/incorrect textures.
• Using the 'change resolution' setting before using entering fullscreen can strangely reposition menu button click areas
• Slight audio desync sometimes
• Driving the car makes the streetlights shutoff at night until exiting the vehicle. A quick work around is to use the car headlights with L
• Using camera movement other than the mouse while driving the vehicle and not repositioning the camera back to the neutral forward position before Exiting the vehicle will cause the player movement to be off by that amount. This is reversible by doing it again with the opposite camera angle.

Let me know if there are any other bugs found and detail as much as you can with it. You can use 'print log' in the console to print out a few .txt files into the LOGS folder of the game directory that has loads of game-play specific info that I can use to debug, so attach them and send them to me as well, along with any screenshots!