Having just uninstalled the game, here's why. The most important reason is the fact that I just got to Mission 11 (which means that I got to around 50% of the game), which is a stealth mission. I haven't even bothered to fire it up. I don't care about stealth missions in my shooter games. Seriously, why put a completely different mechanic into a game which doesn't work that way? At any rate, by saying this is 'the most important reason' I'm just stating that this is what made me uninstall it. But I have many reasons to not like it.
First of is the driving sections. They're tedious. Very, very tedious. They are there only to take you from your point of origin to where your mission is at. They are not enjoyable, or at least they are not nearly as enjoyable as driving in GTA3, which the game can technically be compared to, even though it offers a very different style of gameplay. Tell me this, why do I have to 'manually' go through the same steps (almost) every time I get a mission. Go to a guy for guns (there's no other point to him than a short cutscene in which you get the weapons), go to a guy to teach me how to break into a car (which I haven't done once since I started playing, because there's a number of cars available to you at the beginning of each mission), and only then carefully drive out to the street (using a narrow passage which is hard to drive in). All of this could've been done 'in the background', with no cutscenes and no wasting my time. I guess it's there because of immersion, but let me tell you, Mafia is one of the least immersive games I played. But I'll get to that.
Cutscenes. There's a lot of them and they're long (and mostly have really bad dialogue). You get some sort of exposition every 10 minutes or even more often than that. When the game finally allows you to do something, most often than not you'll have to do something which could've been done in a cutscene (as I discuss in the previous paragraph). When it allows you to take action, the action itself is almost as annoying as the driving sections, even if for different reasons.
It's annoying because you don't get to quick save. Instead, you've got checkpoints. And the firefights in this game can really go any way. I had times when I was dead sooner than I could react, and others when I was under a hail of fire and down to 4 life points, and made it. And if you find yourself having a really small number of life points, but there's enemies ahead, well, you'll have to go through the whole section again, even if you were 'this close' to completing it.
The game is kind of fun for the first hour or so. The 1930's American City is a nice change to the regular modern American City you get in most games like this. The cars are nice, the architecture is cool, the music is alright (it sounds nice, but it's painfully obvious that it has been recorded in our times, and is not 'the real thing'). But the driving and exploring aspect, which is so fun in GTA 3, is just tiresome here. Most cars are really hard to drive - they either turn too much, or too little. The map in the game is confusing and it's very easy to get lost. The speeding limit you usually take just to have cops stay off your back is an obvious issue when you want to have fun. Sure, it's a nice touch that, for once, you can get arrested for speeding in a video game, but in the end, I can see why this has not been implemented in other games.
When I play a game, I don't want it to be realistic, in the sense that I don't want it to make me feel like I'm doing a chore. I enjoy realistic shooters. I enjoy realistic RTS games. I neither of these game genres do we see sections where you're supposed to march for two hours before reaching your destination, or you have to plan with a great attention to details, which soldiers get how much provisions. That stuff is just TOO realistic, nobody cares about that. I enjoyed eating food in Stalker, but if they added a 'poop-o-meter' or 'piss-o-meter' to the game, I'd be pretty annoyed by the distraction. What I'm saying is, getting speeding tickets and commuting to 'work' have little place in an action game. A sim, maybe, I mean, there are games in which the only goal is to sit in the front coach of a train and steer, or to drive on a highway with a truck. But not an action game.
I have to agree with another comment I saw on the net, that this game seems like it started out as an engine with reproduced cars and scenery, and only then did they decide to put an action game in there. The game's design philosophy gathered very good reviews when it came out, but judging by today's standards, there's really nothing too interesting here, unless you're a Mafia fan, and want to play a game about the organisation. I was hoping for a more noir feel, but it didn't come.
Mafia would get a 5/10 from me, but since I haven't completed it, I'm not really sure if it picks up later on, or drags the same way. So I guess I'm just saying you shouldn't be going out of your way to buy this, but if you feel like it and find it somewhere cheap, it may be something you'll enjoy. For me, it's too mediocre of a game to play it any longer, not when I have so many more worthwhile games standing in the queue.