Forza Motorsport busted into the scene in May 2005 on the Xbawks HUGE. It featured a respectable 231 cars to play with on a mix of real and made up circuits, including a street race for all intents and purposes. The game features a frankly strange level up aspect to be able to buy certain cars, but you get some for free (though once you buy Volkswagen VR6 you can print money with a glitch or call yourself tEAm4za). Also it has an option to have a fake carbon fiber hood, a feature yet to make an appearance again. This is slightly off-set by the limited colors you can pick.
Forza Motorsport 2
Forza seems to be better the second go around, probably thanks to being the 360. It displays at 60 FPS at 720P, which while low end for HD now was pretty impressive when this dropped in 07. The car roster has been bumped up to ~309 with 40 cars Downloadable car from Xbawks live (You'll have to track down a copy of the platinum hit's of the game since they' have been discontinued online support). The circuits are still a mix of real and fake tracks (the one's named after snakes) with Twin-ring Motegi being downloadable, but point-to-point street racing has gone AWOL. Livery editing has been changed to include a color wheel instead of just preset colors and there is a 1000 layer limit on each of the paintable sides to help with online racing from becoming a lag fest (supposedly). Also you can choose which tire manufacture to equip with little RPG like differences (One brand might not grip much but will last forever while one is like glue but need's to be changed every other lap), but this feature goes missing in 3. Also in addition to to having a level system, you also get a choice in where you race out of ('Merica, Yuropoor, or Nippon Stronk) which will change prices for cars from similar or different regions (a Corvette will be dirt cheep in 'merica but expensive elsewhere) and even block the purchase from certain cars. You can change regions for a hefty sum though. You can also change the severity of some of the simulation such as damage, steering and was developed alongside the 360 Wireless racing wheel.
Forza 3 was the start of how Forza is now. Intrusive Assists for all but the most brain dead to play but these can be turned off, a Flashback system on loan from Grid but shitty (you can't select where you're placed, and can do it infinitely with no penalty, can also be used to glitch out AI by crashing them then rewinding quick enough). Also the Insta-stop grass is a lot more brutal over previous entry's. Game's still nice though. Leader boards have expanded to tuners and painters as well as drivers thanks to the inclusion of the storefront. The Auction house was also introduced. The game comes standard with ~400 cars in the roster (whipin' out your wallet can bump this to ~500 cars though there is a fair bit of free stuff). Cars can also be tuned to compete in race classes instead of just hitting U Class. Two circuits have been added (Circuit de la Sarthe and Circuit de Catalunya) to the real roster though the Snake tracks from 2 have gone missing. All the variation add up to 100 tracks including a return of Point-to-point tracks. Three also did away with car's being level locked though you still earn free cars time to time to level 50 in the free form career, but introduced the unicorn cars (cars that were released into the auction house that can't be bought any other way). In addition of the 360 Wireless the Fanatec Porsche Turbo S wheel can also be used.
The 4th installment didn't venture far from 3 but features the inclusion of the Autovista mode (gawk at cars and maybe have Jeremy Clarkson tongue your ears about said car), Kinect support, over 500 cars standard (there's plenty of DLC and credits to buy cars with if you hate money though, with some free stuff too) and 26 Circuits. It also lacks Porsche's out of the box but there's DLC for them. Another feature is a choice in which car you receive upon leveling up till level 50, then it just becomes large lumps of money till level 999 (it was originally 150 but people were hitting it too soon) but a lack of info makes min-maxing a bit hard. But if you drive a manufacturer till you get a level four affinity then parts (with some exceptions on rims and aero parts) become free. It's a bit absurd but sure saves money and gives an incentive to drive other brands. It also has some bonus for people bringing over a level 50 profile from 3 which is always nice to see. It feature the same Free-Form career in 3 but you can choose from an event list for to try and get the achievement associated with beating all of them. It also added community designed vinyls to use.
Going by the fact that follow ups are better then the debut for Forza games means you could skip this one. The fact it's on the Xbone mean you SHOULD skip it. But if you committed to an Xbone then pick it up. It's not like there's much else on there. Anyways, Autovista (called Forza vista now) makes a return, this time for all cars with all the Top Gear crew on board for commentary duty. It's less impressive when you realize they only had to comment on 200 cars (before DLC). Some observant readers may notice that's lower then 4's 500 cars (Not to mention Forza Motorsports 231) out the box, and you'd be right. It also has 16 circuits compared to 4's 26. And while Open-wheel F1 cars have made an appearance (thanks to a change in the engine being able to render them) it's kinda token for how many cars are missing. Don't worry though, there's a year of DLC to buy on top of the $60+ game to make up. Also it features a Drive-avatar that mimics how you drive and sends a little virtual you to terrorize other players in cars that randomly select popular livery's from the storefront, which adds much needed flavor to the game. Though if you were negative you could say it was because Turn 10 didn't want to do proper AI. Not worth buying the console for. At least it runs in 1080p at 60FPS and has wheel support.
Xboned & Windows 10
It's the first installment to be avaiable on PC although you need Windows 10 to play it.
So you are Turn 10, makers of the most popular racing video game series but you just aren't attracting the #YOLOswag crowd to drain Shekels via DLC from. What do you do? Contract a small developer to make a game, give them assets from one of your games and tell them to make an substantially worse version of Tokyo Xtreme Racer. The game is however interesting and ain't too bad to not pick up on discount. It' features a sort-of story with various characters you interact with in a fictional event called "Horizon" that is taking place in Colorado which is a nice way to explain why you're driving on public roads like a manic dick. The car roster is diminutive compared to the main series but gets the job done. It also gives info for when you get to choose you're free car upon leveling. Unfortunately Forza Casual is rather short in stock form as there are just set number of events that can be got through easily and once they're done, there's not much to do unless you didn't find any of the barn cars or discount signs (which applies to every thing this time around and is better then "lol, Lvl 4"). This is fixed with the free 1000 club DLC which give each car at least four challenges or the Rally DLC if you drop the dosh, which adds some events and turns all of Colorado's roads to dirt. Shame they never released a full edition like they've done with everything else. Also there is no tuning for cars