Ridge Racer Unbounded is completely unrelated to the original Ridge Racer arcade games. It managed to introduce a lot of new concepts, such as course construction set (with progressive unlock of building blocks), group racing, lots of cars, multiple modes, destructible scenes, and so on. However, with the shut down of the matchmaking servers in early 2015, buggy game (crash to desktop after several races), and odd handling (there is no tutorial on how drift works in this game) means the game, even at bargain basement prices, is not exactly a good investment.
As a new racer joining the scene in Shatter Bay, your task is to "take over" multiple neighborhoods by doing well or very well in the various races. Each neighborhood has about 7 races. Winning the races (or at least, get into top 3) will unlock higher races, while accumulating score will increase your rank and gain you access to better cars.
There are multiple race modes, but most races will be "domination race", where you race up to 11 other cars. Do the special moves like getting air, hit top speed, or drifting, will gain you boost. Once you fill the boost gauge, you can engage boost which allows you to smash through certain "targets", yielding shortcuts that gain you more boost (usually involve getting some big air) but since boost has limited duration, you have to time its use carefully. Smashing other cars will cause them to respawn, albeit several seconds behind.
So what's the problem? Very weird drifting mechanism. Some guides advocate holding down the handbrake button during the turn, others insist on releasing the handbrake as soon as drift had started. The problem is there is no "test track" for you to practice. It's always race, race, race.
The graphics are quite good, and as this is a Bugbear product (makers of Flatout series) the game has decent handling... except for the weird drifting. Sound is... okay, with a lot of decent soundtracks, again, just like Bugbear games like Flatout.
You were able to build your own race courses and as you conquer neighborhoods and raise your driver level you will unlock additional blocks to build the courses. However, with death of the matchmaking servers the courses are of little use now, as much of the fun is race others in MP games. In fact, the game is stuck for about a minute checking for nonexisting server when it starts up.
All in all, Ridge Racer Unbounded tried to do too much and lack of tutorial / test track made the game unenjoyable, and the shutdown of matchmaking server is the nail in the coffin. It's fast, it's furious, but it left an empty feeling.