Mafia 1 Definitive Edition is a complete remake based on both concept art for the original game as well as improvements to existing areas from the original game. Elements from Mafia 2 and 3 are taken as well in order to improve overall quality.
The remake has its team consists of the veterans from the original team, as well as from the teams behind Mafia 2 and 3.
The main aim of the remake, according to Hangar 13, was to make the game with the advances in game design, storytelling, technology and graphics since the original release.

The game is rendered in the modern engine, with improved models, lighting and particle effects. One of the biggest problems with a game as old as Mafia 1 (released in 2002) was that the models were all blocky and pre-rendered. There was no space for emotion and expression for actors, and the special effects were limited due to low processing power.
18 years on, things have changed a lot; everything is now in high definition 3D rendering, the world is living and breathing with the new animations, textures and multitudes of effects.

The one thing that has everyone excited is how alive the world looks and feels; The City of Lost Haven feels like it is lived in by people. The answer as to why is obviously that there is a lot of processing power available now as compared to then.

The city has been remade completely, with new designs added to offer more vistas and points of interest while keepimng true to the look and feel of the original city.

New cover-based mechanics

In the original, Mafia 1’s shooting was straightforward, and often deadly in close quarters due to lack of proper cover, wonky aiming, lack of zoom, and a general feeling that too much was up to chance.

The new shooting mechanics have been changed to have cover mechanics similar to Mafia 3, and better aiming, damage and spread for all weapons in the game.

There is also an emphasis now on Tommy’s new-ness to shooting, and how he gets better over time. The beginning fights are harder because Tommy doesn’t know how to handle a gun, he’s just a former taxi man with a gun. Over time, things improve for him and the gunplay feels better. The gunplay is therefore more lethal, making every bullet count.

Overall, the Mafia 3- but modified- gunplay is a great addition to the remake, as the original gunplay left a lot to chance and old hitscan mechanics that often was crude approximation. Today’s systems are much more streamlined, and the combat is better for it.

New User Interface (UI)

The original game has a sort of minimalist look- the User Interface is only really visible when needed. This is usually during missions when fights break out and street fights etc.
However, normally the world is shown as is, and that’s why it is so enjoyable. Most of the gameplay feels organic, and even when the UI is there, it is tucked away in a corner.

The new UI, however, is a lot more modern and therefore video game-y, with objectives, ammo count, health, the whole nine yards. And it completely takes us out of the atmosphere.

 

Source: Mafia: Definitive Edition – 4K Gameplay Reveal (Mafia 1 Remake)

The original game also did not feature any minimap, which meant players were encouraged to explore and root around during missions, adding to the mystery and challenge. The remake adds a mini-map, making missions feel like they are railroading players into a direction.

The UI also helps finding enemies and “search zones”, so it feels a bit too guided. One of the best memories of playing the original is the confusion, panic and ultimate relief of finding the right path. Objective markers and maps were not there- just directions. It remains to be seen if the new experience is better for the additions to the UI

Sarah gets more screen time

In the original game, Sarah gets very little screen time- but she is the whole reason why Tommy is doing what he is doing. Her story is expanded to reflect her importance in the plot.

 

Mission Expansion

 

Some missions in the original Mafia were repetitive- particularly the car jacking missions given Lucas Bertone the mechanic. These missions have been expanded and reworked to feel less repetitive.

 

Better police systems

 

The police system is reworked; the police will now react differently compared to the crimes committed by Tommy.

 

Overall, there are a host of improvements done for the remake in order to bring it more in line with the modern experience. The Mafia game has remained a classic for two decades and deserves all the upgrades it can get. The most striking thing about the game wasn’t its gameplay, but its story, which is top class.