Madshrimps tinkers with the performance settings of Crysis.

Quote: "Crysis is a system hog no doubt about that, so when we come across a fan community made custom config tool which allows you increase the in-game image quality and improve performance, it is definitely worth sharing.

So we installed this tool on our test system to see how it would impact performance and image quality. The most immediate visual impact is the “time of day (TOD)” modification, which drastically changes the game's look, staring into the sun makes everything else much darker; you can more clearly see people silhouetted against the horizon, while turning away from the sun will give you gradually more detail in the darker areas."
More details on Madshrimps.