Aye, Mafia III was announced last week, but what good does that do you now? The game's not even due until 2016. However, you can today download and play a near-final version of Lost Heaven MP [official site], a mod adding multiplayer to the first Mafia: The City of Lost Heaven.
You and your pals could this very day be zipping around Lost Heaven, chasing each other, and acting like big crimekids in a crimeplayground. That beats teaser trailers and b-roll footage. But, as always with the mob, there are a few complications.
What Lost Heaven MP does have is up to 100 players per server running, driving, and shooting. It also has scripting support to create new game modes; I'll be interested to see what folks come up with. What it doesn't have is pedestrians or the game's story - no co-op. You'll need to create your own playground fun.
Given that the mod's makers have performed the high wizardry of wangling online multiplayer out of a game never meant to support it, one can hardly grumble that it's not enough. The team lead by Roman 'Romop5' Dobiáš been working on it for years, holding occasional public tests. Early versions had synchronisation problems and jerky movement, but it's looking pretty slick lately.
It'll be a little less chaotic than Just Cause 2's fan-made multiplayer mod, I imagine.
The client and server files - so you can host your own - are over here. This is release candidate 1, which means this version's really possibly potentially done, barring unexpected problems. You'll need to provide your own copy of Mafia, of course, which is tricky since it vanished from digital distributors years ago. I gave my disc copy to a pal, thinking I'd buy it on Steam when I wanted to play again. Welp.
Here's a short, ah, gameplay clip from back in April: