There are 326 possible pathways to complete the game.
Due to the mildly violent nature of the game, the ESRB rating was, for a time, in question. The official ESRB website originally had the game rated as T, along with GameSpot, but the official site listed E-10+. The T rating was seemingly further evidenced, however, by the fact that, at trade shows where Sega showed off the game, they asked only those 13 and older to play the title. Early builds of the game even had mild swearing in them, and the game does include two mildly offensive words (damn and hell). For the English Version of the game, Sega took out the human's blood, changed the color of alien blood from red to green, edited the word 'piss' and put 'tick' instead (Sonic says this), and censored the scene when a GUN soldier shoots Maria, cutting out as Maria is shot and falls to the ground. Regardless, the ESRB website later updated the rating to E-10+, thus making it unanimous.
The gun Shadow is holding on the cover isn't actually in the game
Due to the death of Deem Bristow, Sega decided to hire the 4Kids Entertainment's voice actors who were cast for Sonic X (2003) for the "Sonic the Hedgehog" games as well, starting with this one.
This is the first game with Jason Griffith as Shadow and Sonic, along with an entirely new cast of voices from 4Kids! Entertainment's Sonic X (2003) English dub, which ran all the way until 2010 with the last game with the cast being Sonic & Sega All-Stars Racing (2010).