This control method doesn't work quite as well as using buttons, especially if you use the horrible rear touchpad (turn it off in the options right away). (tiredoldhack.com)
But this isn't a lazy port... The game makes use of PS Vita's touchscreen and rear touchpad for added controls and runs at the native screen resolution to give you a genuine Vita experience. (blog.us.playstation.com)
PlayStation All - Stars PS Vita takes advantage of many of the unique Vita features, including «near» functionality and both front touchscreen and rear touchpad support. (blog.us.playstation.com)