It looks like PQube will be releasing a new SKU for Steins;Gate. Amazon has listed a Limited 2016 Calendar Edition for Steins;Gate on the PlayStation Vita with a release date set for the 19th of January. If you are interested, you can preorder the upcoming version with this link from the shopping website.
The product description mentioned that, in addition to a physical copy of the Vita game, the bundle also includes a 2016 calendar featuring artwork from Steins;Gate.
The PS3 and Vita ports of the visual novel came out in North America during the end of August in 2015. As with other games from the same genre, Steins;Gate is heavily story based as there is very little interaction aside from taking phone calls and text messaging. With that said, it offers a compelling storyline, with multiple branching paths, revolving around time traveling.
An anime adaption of the videogame was eventually created. A new installment in the series, called Steins;Gate 0, also recently came out in Japan for the PS4, PS3 and Vita.
So, if you are looking to jump into the series and/or a collector of all things Steins;Gate, you might want to take a look at the upcoming Steins;Gate Limited 2016 Calendar Edition when it launches for the Vita.