I've been forcing AA on Mass Effect 2 since I got it, and it works well; but there are certain settings you must use.
Create a game profile with the below Anti-Aliasing settings, and save them to MassEffect2.exe [%SYSTEM%\Program Files (x86)\Mass Effect 2\Binaries\MassEffect2.exe]:
Anti-Aliasing Mode: Override application settings
Anti-Aliasing Samples: 2-4x
Filter: Box
Anti-Aliasing Method: Supersampling (SSAA)
Morphological Filtering: Off
You'll know it works when you see blurry outlines, almost like mist, around characters in dialogue and cut scenes. If it doesn't work, try renaming 'MassEffect2.exe' to 'UT3.exe'. Best of luck, dude!
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