To summarize, 'Sweet Shop' is a great addition to the franchise that has a few areas needing improvement. Shop customization and 'World Challenge' are great additions, however, the multiplayer is lacking. Overall, it should be a great addition for fans of the Cooking Mama series or a nice introduction for younger gamers.
StarBreak is a game that I really want to enjoy, but it's impossible to look past its glaring flaws. If it was still being actively developed, I could easily recommend it for anyone who enjoys platformers or permadeath MMOs, but it's impossible to know how long the game will even stay operational. However, it is completely free and can be played through the game's website, or Steam, so very little is lost by simply giving it a try.