I finished playing this on Classic difficulty; it must have taken me 12 or so hours to complete it, and my feelings are mixed. When I first started playing, I was very pleasantly surprised -- the opening cutscene was very faithful to the original, suggesting that it was simply going to be a HD remake that otherwise maintained the underlying structure. As the game progressed, however, it became obvious that the new developers had ideas of their own and that, for better or for worse, they were bent on making Mafia an entirely different game. Little by little, subtle changes are shown to have far-reaching consequences, making Mafia: DE a completely different game than Mafia: The City of Lost Heaven, despite both of them having nearly identical plotlines.
One of the most basic changes is the game design philosophy, and this is apparent from the very first chase. The original game was predicated on building a sandbox and having it be a "third player" you had to contend with in order to succeed. You were free to explore and exploit the world as required to fulfill your goals, namely, in the first mission, to wreck or lose a car full of armed gangsters. How you went about doing this was entirely up to you. In the Definitive Edition, however, the devs have already laid out a path for you -- a series of markers that trigger scripted events in which the pursuing gangsters wreck their cars. Losing them becomes a matter of aligning the dots. Is any of the two better? I think they simply represent changing tastes -- the old game had a more subdued tone but more player freedom, the newer one sacrifices freedom for a more cinematic, Hollywood-esque feel. This becomes more and more apparent as the game progresses, as you are railroaded through a series of linear checkpoints and discouraged from applying creative solutions to problems. Want to jump over the railing behind you after assassinating the governor on the steamboat? Sorry, you can't, the devs have scheduled a gunfight among fireworks on the top deck and you simply have to go through it. The barn in a trip to the country is completely linear. In the end, the game's challenge simply lies in your ability to perform mechanical tasks and overcome scripted waves of enemies. Conversely, events have been made "epic" to suit zoomer tastes. Where there was one car, there now are five; where there were five enemies, there are now 20. Where there was a regular chase, there is now a boss fight against an armored car with improbable Hollywod stunts. I'm not saying the original was "realistic", but it was certainly more down-to-earth.
This leads me to another thing I have noticed about the Definitive Edition: it feels noticeably shorter than the original. Not the original was a long game, but a full playthrough would take more than 10-15 hours. I have noticed this is due to several factors. The first one is that they have, quite simply, cut a lot of content. There were hardly any side quests in the original, but you were encouraged to go hunt for rare cars after missions with the Lucas Bertone quests, and this had a positive impact on the game by unlocking rare and desirable cars for you in later missions. In this game, not only do you get all the cars there are to get in the main quest, you also have your pick of vehicles from the garage a la Mafia II, which eliminates most of the incentive behind learning how to steal cars. In the original, Ralphie taught you how to pick an increasing number of car locks, encouraging you to prowl the streets for one to steal -- this could, in turn, lead to its own emergent mini-story as you escaped from the police, wrecked the car in the process, stole another, etc. and basically gave meaning to the open world. In the DE, however, you leave the garage with the car of your choice and have little or no incentives to switch cars en route. In fact, the new system which spawns omniscient policemen and a bounty even when there are no witnesses actively discourages non-MQ shenanigans. As a result, there are many places you hardly ever visit, as there is no reason to visit them whatsoever. The old open world is there, but it has lost much of its raison d'etre.
Strangely enough, I have found the GPS, which is even present on Classic difficulty, to have a huge effect on the game. Tom is a cabbie, and a cabbie's job is to know how to navigate his city quickly and efficiently. In the original game, you acquired the skills of a cabbie organically -- you had a map and it was up to you to plan and design the best routes from point A to point B. As your knowledge of the city increased, you also learned about viable escape routes, place to lose your pursuers or make them crash, and relied less and less on the map and more and more on your gut feeling. By the end, you felt you had a working knowledge of how to navigate Lost Heaven. This doesn't happen in the DE. I had forgotten most of the layout of the city since I last played the original, and after 12 hours of DE I hardly felt I had learned anything about it. This is because the GPS puts your brain on autopilot -- your brain unconsciously pays more attention to following the line than to the streets themselves. I'm not surprised zoomers feel the driving is an unnecessary chore and want it to be skippable, because driving on autopilot is not engaging; it is a purely mechanical task.
When it comes to the story, several reviewers and the new devs themselves have crowed about how they have "improved" it. I don't think "improve" is the word, even though the voice acting is much more polished than in the original. For starters, there is a generation gap between the writers. The first one seems to have been written by fans of late-20th century gangster flicks like Goodfellas and The Godfather, whereas the Definitive Edition has been written by people raised on The Sopranos and Boardwalk Empire. Even though the structure of the story is the same, the tone has changed. The new Tommy Angelo is a strange bird. In the original, he was obviously meant to be Everyman -- someone you, the player, could identify with, a regular Joe who got roped into the world of organized crime. Nu-Tommy, however, speaks and behaves like a wiseguy from the start, chomping at the bit to attack Morello's bar. They have wanted to make him more "badass", and yet he is a lot more emotional than old Tom, tearing up when he accidentally blows up Sergio Morello's wife, preventing Paulie from shooting a waitress, etc. The other characters have also undergone changes that make them entirely different people. In the original, Paulie is a violent, slightly low-IQ thug in the original whose lack of moral inhibitions end up getting him killed. In the remake, he is a comic relief idiot who is deeply frustrated with his life. In the original, Sam is a cold-blooded killer who values loyalty to the don above friendship, whereas in the remake he is an opportunist with a yellow streak. Don Salieri has been "Sopranoized", for some absurd reason they made Frank talk like Lyric Suite, giving him a FOB Italian accent even though he's been in Burgeristan for over 40 years, and they added some bullshit story about a greyhound so soyboys could empathize with the heckin' doggerino (in order not to upset Reddit, shooting dogs is haram in the DE, btw). The reviewers rave about how Sarah is more relevant now, but they just made her a stock current year Stronk&Independent Wombyn who makes Tommy feel bad for murdering the guy who enacted women's suffrage. And for no reason at all and to no benefit for the gameplay, they made Salvatore only speak Italian, but instead sounding like a terrone he speaks like the voices in a Parla e Scrivi textbook.
I find the ending to be particularly bad. It's amazing how, despite largely following the script, they completely altered the tone -- instead of a gloating, self-sufficient Sam showering you with dirty money as he revels in having manipulated his long-time friend into falling into a trap, we see Sam scared and insecure, despite having somehow had the time to prepare a huge ambush in the gallery even though Tommy only told him to meet him there a few minutes ago (in the original, it was clear he had planned it from the start). The original ending finishes on an anxious note -- rather than beg for his life like in the DE, Sam taunts Tommy, predicting that he will end up killed all the same, revealing Frank and the whore's deaths in an unexpected revelation. Thus, while original Tommy lives in fear for the rest of his days, his distorted face a testament to the fact that crime doesn't pay, nu-Tommy dies smiling, like a philosopher, happy that his family is now "safe" (why? Salieri didn't hesitate to bump Frank's family, why wouldn't he bump his?).
Finally, I would like to add a note on the sound. I appreciate the fact that they wanted to add radio stations, but I felt I enjoyed this game's soundtrack a lot less than the original's. I can do without the fake broadcasts and cigarette advertisements written for zoomers who see the 20th century as a strange and exotic time ("lulz doctors recommended cigarettes they wuz strange amirite") and generic lessons on world history. I'll take some good Django Reinhardt over LARP radio anytime.
So much for the bad things, what about the good ones? Obviously, the graphics look amazing. They have obviously put a lot of work into the city and they were faithful to the spirit of the original by updating its appearance as the years go by (newer cars, liquor advertisements after prohibition). The streets feel crowded and alive. The addition of motorcycles is nice, but a wasted opportunity since you only really have to ride one once. The shooting mechanics are not bad, and the enemy makes a very aggressive use of fire and movement that prevents it from degenerating into static popamole shootouts. Cops reacting to more infractions, such as driving on sidewalks, is a welcome addition to keep you from getting too crazy if you want to go unnoticed. The game was an enjoyable experience overall. However, I do not think these strengths would have been enough to make this game a hit like the original was as there is simply not enough to keep you entertained to make this anything other than a 10-15 hour diversion worth playing out of curiosity or nostalgia.