It can be a bit tricky to play with two cats at once! The game that I tried to play was very simple or so I thought! I would call them by their name and throw treats far away for them to chase however I noticed that both of them would chase the treats. This led to them fighting over who gets the treat.
Also, it appeared that one of the two cats would just stop playing because the other cat was being aggressive. I tried to train them for a couple of days but it was not working well.
So instead I tried a different approach. I decided to assign the cats specific paths to run in different directions of the house, I would still be calling them by their name when throwing the treats but I would not let them go into the other cat’s path.
After a bit of training, they stopped going into the other cat’s path fighting over the treats. The cats realized quick that during play, the specific path assigned belongs to them. This is prolly the simplest game I could think for me to play with both of them at once.
You could also try to throw treat for either cat when the other one is running. If both of them see you throwing the treat, then they might get confused sometimes and try to go in the other cat’s path. You want to avoid them crossing into the other cat’s path as much as possible during the initial training. It’s okay to tell them “No” so that they know when they go into the other cat’s path during playtime it’s wrong.