I just showed it to my girlfriend, she's hardly impressed, and she has some good points. Visual sensors require a lot of light to function. This will give "eye of judgement" problems. If your lightning is wrong, it won't work right.
Also she studies voice therapy and knows a lot about voice recognition. There are major facilities working on getting it right, but so far the results are far from perfect. We all know from software that we tried that Voice Recognition can be a real pain; often it doesn't understand.. you don't want to be dependend on that in your game. If you 'die' in a game because the software doesn't understand, that is really going to be frustrating. If you have an accent, you are tired, you have a cold etc etc.. the software won't understand. You have to teach it "your voice" and takes a lot of time, not to mention processing power.
The video with the boy, shows stuff that is impossible. The boy might be able to react on words, but the dialog was pre-recorded, no way a computer can sound like that.. nor can it think by itself like that, AI is not that advance at this point at all. This means that if you experiment too much, the boy will not understand or will show wrong behaviour.. it's a nice video, but you should hold some reserves in trusting the interactivity.
All-in-all it looks too good to be true, and there is a saying:
When it looks to good to be true, it usually is.
We also have to keep in mind that processing this amount of data consumes a lot of the processor power, this will mean the graphics for games that have it implemented will be majorly decreased.. it might attract new gamers to the market, but don't expect a MGS5 with motion sensing just yet.
Last but not least, we're talking about microsoft here. They never managed to get windows® to work, it's probably the last company in the world to get this kind of technology to work flawlessly.
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But I talk like a fanboy now. I was impressed by that video, period! If they DO get it right, they'll have a selling hit in their hands.. I'm still not going to buy it though. I'm absolutely sure it will take 2 years before they "could" make a good game with it, it will just be minigames wii-style for now, and that gets old pretty quick.. that's what we can expect I think
The exclusives that were shown didn't have my interest either.. not if I'd compare them to Uncharted 2, Heavy Rain and Fat Princess. And I don't have time to play them all. One console is enough for me.