I work for Feral (we developed Borderlands on the Mac) so I do know Borderlands does have some side effects when playing on a Intel HD3000. The biggest issue is some decals etc are rotated 90 degrees and changing your resolution while playing the game results in a permanent black screen. These are side effects of missing features in the drivers compared to other cards in older MacBookPro machines.
We are working on building up a list of the issues with the HD3000 and also thinking about how we can disable certain graphics options or alter our methods to get around the problems. If you notice issues with any Feral game on your 13″ MacBookPro please email our support team so we can make sure we look into it and more importantly let you know when we have a solution.
Cheers,
Edwin