I'm not sure how many of the 311 that have joined(it may be more now, but that's the last number I noticed) will actually manage to submit. I know that there have been several who have declared that they were not able to complete their submission for one reason or another. Then you will have the inevitable list of people who don't fit the qualifications for one reason or another. Many of the games won't be a full hour of gameplay. I wouldn't be surprised if there are more 30 minute games than full hour ones.
Either way, this will take some doing. I'm guessing that the fan favorite candidates will end up getting narrowed quickly as people will choose which games to spend time trying out based on descriptions and screenshots. It would be interesting to hear how long the judging period would be, however, as if there are even half of that number of hours worth of submissions, it will still take over a month probably (I'm guessing that unpaid judges aren't going to work 8 hour shifts for a month to judge this contest.)