Out of all the games I play this game makes my system run the hottest.

My video card is reporting anywhere from upper 70's to 80 C, and my core's are running in the low 60's C.

Must be the excellent shadow and lighting effects.

--Just looked at a previous post--playing this game with v-sync enabled cools the system down alot when playing this game...

Still one HOT Game, though

I recently began playing and my GTX470 runs around 80-85C as well but that's normal when SSAO is used. If you lower that setting it should decrease temperature which is, BTW, a very subtle difference and hard to notice.

Switch VSync on.

Just so you know, VSync should be on by default if you are using the patched version

additional, you can lower in the grimrock.cfg the preconfigured maxFrameRate = 120 (which is too high) to something around 30 fps whcih should be enough.
Before setting maxFrameRate, you should check your actual fps in-game by activating "debugInfo = true". You can achieve an cooling effect only if you set the maxFrameRate value below the actual, achieved fps. (e.g. you have in the mean 70fps, set maxFrameRate to 30fps and you save your GPU the work of generating 40 fps -> lower temperature)