Custom game modes or tags allow the use of alternate gameplay rules and types in Audiosurf. Some of these rules change only scoring, while others make drastic alterations to existing Characters or track shapes. To try these out, one must edit the song's track title from its ID3 tag and add a keyword in brackets. For example, if a song has the title All Along the Watchtower, to play it with no Stealth bonuses allowed, you would have to edit the title to All Along the Watchtower [as-nostlth]. There are some add-ons such as Audiosurf Prodder that can automate the process of re-tagging.