Doom

How many instructions does a processor need to execute to get through the first level of Doom?  About 2.7 billion, in my case.  Over the course of the several minutes it took me to stumble through the level, it rendered about 1080 frames, each of which required about 2.5 million instructions to produce. The other 700 million instructions initialized the game, loading textures, setting up data structures, etc. 

"It works in the simulator..."

I do most hardware development in simulation. It allows a level of visibility that software developers can only dream of: I can see the state of every signal at every instant for the entire run. But there is a dark side to simulation: the synthesized design may not behave the same as the simulation. There are a few well known patterns that lead to synthesis/simulation mismatches that are easy enough to avoid with attentive coding, but the existence of these gremlins always leaves me uneasy...