A lot of people are going to tell you not to bother with a VM. Ignore them. If that's the way you want to do it, do it. Depending on the game, I personally use a mix of Boot Camp, Wine and Parallels VM, so I'm a big believer in using the tool thats fits the job best.
As I said, I use Parallels, not VMWare, so I can't say for sure. Do you have VMWare's 'additions' installed (I think they call them VMWare Tools maybe)? Their own drivers that you install to integrate Windows with Mac OS. These are usually required for any type on 3D gaming on a VM.
Don't give up. I can get C&C First Decade running great with Parallels. You should be able to do the same.
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Another thought is that you are trying to play First Decade on Windows 7. Most won't run properly on anything higher than XP without some tweaking.
For RA2, you'll want to run in XP compatibility mode, and Run as Administrator. This may work for the others too.
