MacBook Pro Heat Damage

I would not worry just yet. If you regularly make it a true laptop (sitting on your lap on a blanket) the bottom panel cannot dissipate heat as designed. If you block the rear of the keyboard section you block a heating vent.

The MBP will know if it is too hot and protect itself with shutdown-like behavior before major damage.

Heat management is not tied to software type. It it tied to the detected system energy usage. The worst you will probably encounter is that when the CPU/GPU starts to get close to "too hot" it will throttle the system ... slow down the system a little ... to prevent overheat.

Just when needed. It probably is altering system speed once a minute, you just do not notice the change in performance because your attention is distracted from the game response by little things around you.

Play games as you want, let the hardware do its work. You just need to start worrying if the system gives you alerts.

Have fun.