I was thinking of creating this topic for a very long time. Playground Games deserve immense praise that I think they still aren't getting. They really pack a formidable talent in their ranks, comprising industry veterans of Codemasters who are responsible for legendary PS1 games (which I loved to death and loved PS brand back then like cows love now PS4) such as TOCA and Colin McRae Rally (as well DiRT), as well as ex-Bizarre Creations developers (of PGR fame).
I'd even go as far as to say that Forza Horizon is Arkham City of racing games. It has its flaws, sure, but I think they'll all be but gone in the next installment.
Everything related to exploration is so meaningful in this game because you are either rewarded for everything you do or you can compete against everything you do vs the whole community of human players:
You have discovering of new roads (which count towards achievements), you have speed traps (measuring your top speed in a singular points) which count against whole community as well as speed zones which measure your average top speed in a selected zone. You can challenge other AI racers to a one-on-one race in any place on the open-world map, you must demolish special discount signs in order to get reduced prices for car parts. You have barn finds which are old derelict cars abandoned in barns that you have to find and once you find them they are renovated by your sidekick and added to your garage. Moreover, you also have Outposts which are locations to which you can fast travel for a price once you discover them but you can fast travel there for free once you complete three types of challenges each one of them offers: one of them is about going to a particular place of interest not damaging the car in the process and taking a photo with a required landmark in the background, second one is about reaching a certain top speed by the speed trap, usually in a car that can kill you if you push the gas pedal too much, and the last kind of task is to reach certain amount of skill points for drifting, destroying road signs and other road skills, such as J-Turns, burnouts, etc.
Speaking of which, you also have sponsor challenges which give you additional cash for performing selected stunts given number of times, as well as your reputation increases when you perform road tricks and stunts, you begin at the 200th place which also has its separate achievements.
Not to mention the races themselves which sometimes require you to use alternative paths or pit you against an airplane, helicopter or an air-balloon. Alas, admittedly there could've been even greater variety in races, but that is going to change with Horizon 2.
As you can see every single detail is meticulously tailored towards community-oriented gaming. Forza Horizon looks so stunning and eye-pleasing that even my wife - who absolutely hates gaming and is a non-gamer - a couple of times had a desire to take my Bugatti EB110 for a spin and took over my Xbox. You cannot get a better recommendation than this.
Presentation is slick, every single aspect is polished to the highest level, for example soundtracks which feel really special and they have a hand-picked vibe to them. It was a gigantic enterprise all around. The atmosphere is really amiable and with such a multitude of tasks, challenges and events, it's a joy to play. What's more, it is really immensely fun to free roam without even completing any kind of an objective.
Playground Games are, in my opinion, one of the best racing game studios at the moment.
Horizon 2 is going to add dynamic weather, 1080p, perk system, true free-roaming with virtually no barriers (Test Drive Unlimited 2), with seamless, instant multiplayer with 0 waiting and no traditional lobbies, is going to feature town-based races a'la PGR. The only thing that's preventing it from becoming an ultimate racing game is the inclusion of police.