To dispel any rumors, the Flash game was on SoA's website ages ago, and plays nothing like the phone game, which is just ye olde Sonic 1, but on a phone.
The plus side, though, is that the phone version actually has some things from the Sonic 1 beta, like purple flower-insides for the sunflowers in GHZ, or the UFOs in Marble (albeit sadly only in VRAM, and not actually displayed - Marble looks as it ever has). Otherwise, it's just, again, Sonic 1, on a phone. Nothing new at all, except maybe the HUD, which is a minimal thing.