SEGA holds the copyright to Sonic the Hedgehog. Sonic XG is a non-commercial tribute. It is freeware. If a website asks you to pay for the "Sonic XG Android download," you are being scammed.
On a mid-range Android (e.g., Snapdragon 732G), Sonic XG holds a steady 60 FPS at native resolution. Touch controls are customizable, but I strongly recommend a (Xbox, PS4, or 8BitDo) for the best experience. Sonic Xg Android Download
Over time, fans have created unofficial Android ports or modified APKs to run Sonic XG on mobile devices. There is from the original creator (XG Team). Any Android download is a third-party port or emulated version. SEGA holds the copyright to Sonic the Hedgehog