Modern games are written in huge swaths of C++, tiny bits of SIMD compiler intrinsics and individual pieces of very special-purpose assembly.
If you want to feel impressed, check this out http://benfry.com/distellamap/
If you want to feel impressed, check this out http://benfry.com/distellamap/
I don't think I've seen any assembly that was actually enabled in the games I've worked on in the last five years, though I do know where there's a tiny bit in my current project that's #if'd for older environments. That's just stuff like atomic operations that every modern compiler provides built-ins for now.
The link is great, thanks!