All games entered for GGJ are released under a Creative Commons share, alter, no sell license. You can browse through the games and download their source files on the official website, and a couple of publications did quick hands-on playthroughs.
"Although the club is focused on game development, not everyone participating was a computer programmer. Artists and graphic designers were present to help create characters and models for the games. The goal of Global Game Jam is to a stir up a global creative buzz in games while at the same time exploring the process of development."
You can read all of these proposed final solutions in Matteo Bittanti's How to Get Rid of Homelessness, "a 600-page epic split in two volumes documenting the so-called 'homeless scandal' that affected 2013's SimCity." Bittanti collected, selected, and transcribed thousands of these messages exchanged by players on publisher Electronic Arts' official forums, Reddit, and the largest online SimCity community Simtropolis, who experienced and then tried to "eradicate" the phenomenon of homelessness that "plagued" SimCity."