When gaming, your SP2 will get very hot if you are running it at full speed (ie. 100% CPU clockspeed, maximum graphics performance). As long as you are using your SP2 in an appropriate environment (ie. in an open area where it has proper ventilation rather than under a blanket or in a case that blocks the vents), it will underclock to stay under 80 degrees Celcius. Intel CPUs are pretty solid and can definitely go up to 90 degrees and may even go up to 100 degrees without any damage unless you run it there for a significant period of time but, again, the SP2 is designed to throttle once it hits 80 degrees. The fans should be going at max speed if you've gotten it to 80 degrees.
If you are concerned about that temperature, however, there are steps that you can take to limit how much of the CPU and GPU your game uses. Firstly, you can set your SP2 to never go above its minimum CPU clockspeed. You will find this setting in your power profile (you can find that by left clicking the battery icon in the lower right and selecting "More power options", hit "change plan" for whichever one you want to use for lower power and battery use, and go to "Change advanced power settings). Scroll down to "Processor power management" and set the "maximum processor state" to 0%. That will prevent the SP2 from ever increasing the CPU's clockspeed which will reduce power consumption and heat generation.
You can also throttle your Intel integrated graphics by going to the "Intel Graphics Settings" option in that same panel and setting it to "Maximum battery life". This will prevent your GPU from being used fully, thus reducing heat and battery consumption. Do note that limiting the CPU and GPU will slow down your system's performance but you will get much better battery life as a trade-off.
Finally, you can limit the framerate and graphics options in the particular games that you are playing so that it won't use your SP2's now limited capabilities fully. If your game doesn't have a built-in framerate limiter, the simplest way is to just lower the settings to the minimum, play at 720p (or lower but then things start scaling poorly on the SP2's 1080p screen), and turn v-sync on to limit the framerate to some derivative of 60 fps. There are more specific ways to limit your framerate with 3rd party programs but I'm not sure how well they work with Intel integrated GPUs so I will leave it at v-sync.