Linux Mint 12 uses GNOME 3 by default, and they have included a series of "Shell Extensions" with which users can customize their Mint desktop. One of the key features, here, is the Menu shell extension, which adds a menu panel in the bottom-left corner of the menu bar that looks and feels similar to the standard Mint menu users remember from earlier versions (and which is still available by logging into a MATE session).
Crossover's primary menu items - Manage Bottles, Install Software, etc - will appear in the Menu shell extension, but Windows Applications/Windows Games, and the enclosed launchers, will not. To find applications you've installed in Crossover from the Menu shell extension, you'll need to search for the specific name of the application (similar to what's currently needed in Ubuntu's Unity interface with Crossover).
However, using the "standard" GNOME 3 menu, as accessible through the top-left corner of your desktop, you will find Windows Applications/Windows Games correctly organized as separate Applications groups.