NVIDIA 3D Settings

For NVIDIA graphics do the following:
Open NVIDIA Control Panel
Click Manage 3D settings
Click the tab Program Settings
Click add and browse to C:\illusion\AA2\AA2 English.exe (for the Maker you should use C:\illusion\AA2Maker\AA2Edit_English.exe)
Recommended settings for maximum visual effect:
Anisotropic filtering: 8x
Antialiasing - Gamma correction: On
Antialiasing - Mode: Override any application setting
Antialiasing - Setting: 32x
Antialiasing - Transparency: 8x (Supersample)
Texture filtering - Anisotropic sample optimization: Off
Texture filtering - Negative LOD bias: Clamp
Texture filtering - Quality: High quality
Click Apply
Experiment with lower settings if you don't have a recent graphics card or to tweak performance vs. visuals.
ATi/AMD 3D Settings

For ATI graphics do the following:

Open AMD Vision Engine Control Panel
Click Gaming
Click the tab 3d Application Settings
Uncheck the Use application settings checkboxes under the Antialiasing and Anisotropic tabs.
Recommended settings for maximum visual effect:
Antialiasing - Setting: 8x
Antialiasing - Filter: Edge-detect
Anisotropic filtering: 16x
Catalyst A.I. - High Quality
Catalyst A.I. - Enable Surface Format Optimization
Mipmap Detail Level - High Quality
Antialiasing Mode - Super-sample AA
Note: Supersample AA can bring even the most powerful computers to sub 30 FPS in this game during H-scenes and conversations. If you find the FPS drop to be unbearable, Adaptive Multi-Sample AA is close to the same quality with drastically less of an impact on FPS.
Click Apply