Yep, a lot of people seem confused by the overwhelming positivity, but I've explained it in other posts, a lot of people just fake being super positive and then give you 1-3 stars just so you can "return the favor" hoping you thought they were so positive they gave you 4-5. And also they don't want to be negative or critizice your game in fear of you being offended and retaliate with a low score.
As I said, my advice: join smaller jams, <200 participants, people are way more awesome, less dishonest and less competitive and (mostly) genuinely vote and tell you how to improve your game. It's less competitive and more cooperative.
Also, some people were 1-staring games just to boost their own. So yeah, somehow, with all the amazing games, the amazing art of some games, the amazing ideas, the amazing mechanics that I've seen in this jam... the winner is a simple unpolished unoriginal puzzle platformer with crappy pixel art graphics (and getting a 4.0 in visuals!!! WTH??) and no music. Some things just don't add up, but anyways, it is what it is man...