There is voice acting in the mod much like Portal Stories: Mel. Aperture Tag is extremely cheap going for about $3-4USD. Unlike Portal Stories: Melwhich was a free standalone mod, Aperture Tag is a paid mod (fan-made) that requires Portal 2 installed, otherwise it will not launch.
Why test with portals, when you can use gels!
Aperture Tag: The Paint Gun Testing Initiative is a paid Portal 2 mod available on the Steam Store.
