Performance upgrades and skills
In the initial release version 4 (July 20, 2010), car performance could be improved via street or pro upgrade kits (purchased with in game cash), depending on the car. Some cars only had street upgrade kits as an option, and the fastest car in the game at the time, the BMW M3 GTR, did not have any upgrade kits. The game also had "driver skills", 3 of which directly improved performance (acceleration, handling, top speed) and applied to any car that a player was driving. The skills unlocked as a player leveled up and a player could select up to 49 of 81 possible skills. Once a skill was chosen, it couldn't be undone, and players would have to start with a new driver or account and level up again in order to choose a different set of skills. In November 2010, with version 5, the upgrade kits were removed and replaced by performance parts, each car having its own set of performance parts. In May of 2012, "driver skills" were removed from the game and replaced with skill mods, each car having its own set of skill mods. There were no performance skill mods to replace the acceleration, handling, and top speed skills, so the cars ended up being slower. The lowest rated parts or skill mods could be directly purchased for free using in game "cash", but higher rated parts or skill mods could only be won by chance from card packs, either free "lucky draw" card packs rewarded at the end of any event, or card packs purchased with real money converted into the games microtransaction currency called "speed boost".
Visual aftermarket parts
On March 16, 2011, visual aftermarket parts were made available, and later added to lucky draw in December, 2011. All the in-game cash bodykits from previous versions were removed. Most body kits required SpeedBoost to purchase on May 31, 2011.
Night Mode
Main article: Night mode
In December, 2010, night mode was added to the game. This required adjusting the night mode lighting via a brighter moon, as the part of the map that came from Most Wanted had light posts that could be knocked down by a players car. Since Carbon was a night mode game, almost all light posts were located so that players cars could not knock them down, so this was only an issue for the Most Wanted part of the map.
Holiday Themes
In September, 2010, an Oktoberfest theme was added to the game in the form of decorations to parts of the map. In December, 2010, a Christmas theme was added to the game, and included snow and hills added to the golf course. For New Years, the game would go into night mode for 24 to 48 hours (depending on year), with fireworks at some spots in the map.
Team Escape Mode
On March 31, 2011, Electronic Arts introduced a new game mode called Team Escape, a semi-cooperative version of a police pursuit where up to four players participated in a sprint from point A to point B while avoiding numerous cops, within a set time limit depending on the event. For this mode, two team versions of the game's power-ups were released.
Treasure Hunt Mode
On July 26, 2011, a feature called Treasure Hunt was released. In Treasure Hunt, played during free roam, players would attempt to collect fifteen gems located in various areas. If the player collected all fifteen gems daily, they would get boosts of reputation and in-game cash. Playing the Treasure Hunt mode daily would build up what was known as a Treasure Hunt Streak. Players earned random high-end performance parts or additional power-ups after completing every hunt based on the day count of the streak (for example, if the player completed Treasure Hunt for twelve days in a row, they would receive a random tier 1 pro performance part). Players doing treasure hunts were unintentionally getting into pursuits since ramming a police car while in free roam triggered a pursuit, so on November 16, 2011, police vehicles were removed from free roam in World . Players were no longer able to start pursuits by ramming police vehicles; police chases were only possible by joining Pursuit Outrun or Team Escape events.
Drag Mode
On October 16, 2012, drag racing was introduced to World. This mode allowed players to race other players to the finish line in various strips of straight roads. Players would need to use manual transmission and shift their way to the finish. Automatic transmission was also available to the players. Single-player mode was also made available with in-game traffic.
Achievement Mode
On April 10, 2013, an opportunity to win valuable in-game rewards by completing various achievements was introduced. The old player achievement system that only showed a players stats was dropped, and replaced with the milestone based achievement reward mode.
This aggravated the pre-existing and largely ignored problem of cheating in the game. Prior to this, client side cheat detection could be defeated by game hacks, so some server side cheat detection was added, but due to being prone for false detection of a cheat, a "detected" cheat just meant there was no post event rewards. The existence of the problem was finally acknowledged by a Community Manager on April 15, 2013. However, Quicklime Games, which was in charge of game development, maintenance and updates, was shut down on April 25, 2013, so virtually nothing was done to improve cheat detection, and instead the focus was to ban players "caught" cheating with the existing cheat detects, but this resulted in innocent players getting banned, which put a burden on EA support to undo unfair bans.
