The San Andreas, Liberty City, Vice City, Manhunt I/II, Bullworth, and custom maps combined into one big map. With gang wars, shops, added (not replaced) vehicles, peds, and weapons (yes, you can modify added vehicles and buy added weapons in weapon stores) in the same style as if R* were to make an expansion for GTA: San Andreas.
Snapshot 2.2 is a version released in August 2016, but was never uploaded here.
Snapshot 2.2 is the final version built upon Snapshot 2 and Snapshot 2.1. It fixes a lot of bugs, and improves a lot of things.
The next release, Snapshot 3 will be the final snapshot version and should be pretty much bug free. But for now, you can play this version.
For any bugs, please visit the GTAForums thread (http://gtaforums.com/topic/776561-wipbetasa-gta-underground-mod-discussion/page-404), the bug tracker (bugs.gta-underground.eu.org), or even the official forum (forum.gta-underground.eu.org)