I've now had about 2 hours worth of racing and thought you might be interested in hearing some initial thoughts.
Driving Physics - I thought Forza 2 was supurb - Forza 3 has just added to the overall experience - There's a real feeling of weight to the cars, and with Turn 10's mapping of each individual tyre's physics - you get a real feel for driving on the track - you can feel when your car's reaching the edge of it's line - just amazing.
One of my favourite new features is the automatic upgrade system. Whilst you can completely customise your car for each race including buying new parts and adjusting the settings - Forza 3 offers an automatic upgrade option to ensure you are competitive for each race - Very clever, very useful, and very awesome.
Graphics - Everything's better than last time - Track environments are lush with detail, and the car's themselves look fantastic. The big addition this year is individual in-car views for every one of the 400 or so cars currently included. And all of this running at a silky smooth 60 fps!!
Career mode is now much more interesting, and is customised to your current vehicle, and offers events that you can enter with your current cars - The events appear on a calendar, so you can plan ahead, and each event is unique to your career as it currently stands. This makes it way more engrossing, and keeps you coming back for one more race - nice.
You obtain new cars by buying them with the cash you win in races. Some manufacturers give you cars based on your performance. In addition you can purchase cars from manufacturers all over the world. The online auction house returns where you can find great deals on new cars and customised cars.
Car editor - The editor has built upon last year's editor system - Its pretty easy too, as evidenced by my 11 year old son completely customising my Citreon C4 VTS with his 'mad skills' design. I think we'll be spending a bit of time customising all of my cars.
Race Modes - Career and Events, Quick Race, Hot Lap, and Split Screen (and don't forget the awesome 3 screen mode which you can do using 3 screens to simulate the front and side views - Great if you have 3 xbox's, 3 copies of forza, and 3 big screens - I'm definitely gonna do this with some mates). Multiplayer has open public races, and private races, where you can customise the racing event to suit your friends (This is where we'll run our NZ Racedays from).
Community features - Yep Forza 3 has a host of great community features which build upon Forza 2 - The auction house return for you to 'buy' using your race winnings other peoples cars, setups, and liveries. You can even set up you own storefront to sell your own creations including cars, designs, decals, and even your own race setups - awesome!! You can save full race replays in single player, and multiplayer modes, as well as take photos. You can even create short movies from your replays, and photos and movies can be uploaded to your space at ForzaMotorsport.net. Here you can engage with a worldwide Forza community, and share your moments of glory and pain with anyone. In addition there's a really detailed set of leaderboards where you can see how you stack up against friends and the world from individual tracks to whole vehicle classes.
I'm still really early into the experience, but so far I'm loving every moment of this great game.
Feel free to add your experiences so far below....
This posting is provided "as-is" with no warranties, and confers no rights.
