Coming in I didn't have high expectations, as it became obvious to anyone that PD is lagging behind and will release a prologue like game. So maybe that's why I'm not as disappointed, I knew what to expect. My impressions:
Graphics- I'm not disappointed on this front, the graphics are good enough for me, I'm more concerned with content. GT has good graphics in it's own way, and Forza has it in it's own way as well. Forza is more colorful, bright, less gloomy, more lively. I do agree that the environment needs work, but the level of graphics is good enough. The car models look better to me. That's not enough to win me over, I think Forza car models are also good, and they have many more premium cars.
Physics- I like it, seems like every move and millisecond matters. The suspension is working, even on the straights I could notices the vehicles suspension adjusting over bumps, minor bumps. Physics is what won me over for GT(started playing at GT5P), there was no alternative at the time on playstation. I believe the racing will be competitive, if the online mode doesn't have connection issues and there aren't people trolling. I noticed some were upset over collision physics, I'm upset with rate of development/content more and can give them a pass here.
Sound- Maybe I'm wrong but the engines sounded like they were working hard, the sound still is familiar but it's there's more energy and passion to it. Previous GT's, I noticed no suspense or change of tone going across the power band, in this GT I do notice a change, which is good enough for me. It doesn't seem like a complete overhaul yet, will need to see more footage though.
Damage- Some people are stating damage was disabled for the event, and that it is a thing. I'm not sure, so we will have to wait on that front. Do I want damage? I would like it on Forza's scale, not much more than that, however.
Platform- The new menu looks clean, so does the new font. Similar to GT6, which I didn't have a problem with.
Content- Knew what to expect, honestly. PD is lagging behind badly, I'm not even sure what they're focusing on anymore. The competitor put out a full game in Q4 2015, that impresses me with the content. The graphics are great on Forza, in it's own sense. There are enough cars, and the car list is really nice, they secured lots of big name brands and the most fascinating cars of these brands. That are all fully modeled. The customization is very wide on Forza, they have packed campaign mode and some other fun modes. On other hand, what we get is a smaller game, that might not even have career mode, with 140 cars, some of which are not real. So know we know not to expect GT7 until late 2018 probably. This rate of development is bothersome. I got a PS4 primarily for GT and Uncharted 4, Naughty Dog has delivered, PD, however, is under performing big time.
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So is it a huge disappointment? Depending on what you were anticipating, I had no high expectations once it was clear the title is not the seventh installment(technically). I'm contemplating getting an Xbox at this point, but debating if I should go that route or try this GT plus AC along with a steering wheel setup. The racing in Forza doesn't seem as competitive or fun, it seems milliseconds and every little input is not important in Forza, rather the overtaking happens abruptly. Everything else, however, is great. The content, sound, damage, graphics blows me away on Forza.