@cay64709 since an external monitor works it is likely that this is related to your computer's display assembly. Not sure if the game issue was just coincidence or if that messed with the display settings. You have restarted your computer and hopefully you have tried to check your BIOS to reset that. Right now, from what you are describing, it sounds like you will need a new display. Use something like [https://www.youtube.com/watch?v=C9RqRZgJa7I|this video] to work on it.
Of course, you could also try and see if something like this will help to clear any issues if this was caused by installing the game. Disconnect the power from the computer by unplugging the power cord from your computer. Disconnect all external devices from the computer. Remove the battery Now hold the power button depressed for about 30sec-1min. Reapply the AC power adapter and see if your computer display now shows any sign of life.
While you work on your Asus, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.
Repair is War on Entropy!