Season mode has been lengthened to two in-game years and features the Brand Extension featuring Ric Flair's Raw and Vince McMahon's SmackDown!. For the first time only male wrestlers can participate in season mode. Players compete exclusively on the show they are drafted to for the first few months of year one, consisting of four Raw or four SmackDown! events, plus a monthly pay-per-view event. If the player's character is a created superstar, or if the original superstar has a rating lower than 60, he will instead wrestle on Sunday Night HEAT. Eventually, the player will be booked on the two major TV shows, appearing on two RAW and two SmackDown! shows and the PPV event, even if he did not hold the Undisputed Championship. One of the major angles featured is based on a nWo storyline featured in early 2002 that included Hulk Hogan, Kevin Nash, and X-Pac, who replaced the released Scott Hall from the original televised storyline.
Like its predecessor WWF SmackDown! Just Bring It, Shut Your Mouth's championships cannot be contended for in Exhibition mode and can only be defended in season mode. All of the major titles of the time, except for the WWE Women's Championship are included in the game: WWE Undisputed, Intercontinental, European, Tag Team, Cruiserweight, and Hardcore championships. Various unlockables such as alternate player attires can be unlocked through Season mode.
Televised and pay-per-view events are televised from the SmackDown! Arena, the exterior of which is based on Madison Square Garden. Although Jim Ross announces a different city at the start of each events, the exteriors remain the same. Notable areas are a New York Subway stop named SmackDown! Station, Times Square, and The World. The game features several arenas that WWE held events at in 2001 and 2002. There are also arenas based on each WWE television show. In certain arenas, players could make their wrestlers scale the TitanTron and jump off it. In addition, The Undertaker's motorcycle could be ridden in some matches.
Create-A-Superstar mode gives the freedom to manipulate any part of the superstar's body. It also offers over 58 move sets from a combination of wrestlers in WWE not featured in the game or working in different promotions.
Wrestler models were greatly improved, and included realistic facial features. Fully animated entrances for each character are featured, with their entrance video playing on the TitanTron, and their respective themes playing in the arena. The title belts are also displayed in the entrances realistically (e.g. Brock Lesnar carrying the title belt to the ring and tossing it above his head).
For wrestler entrances, most of the themes used in the televised and house shows were incorporated into the game. Along with the in-house music from Jim Johnston, remakes of Johnston's originals from bands such as Breaking Point (for Rob Van Dam), Our Lady Peace (for Chris Benoit), and Saliva (for The Dudley Boyz) were featured. However, Maven and The Hardy Boyz do not have their correct themes, however Maven's Theme is hidden in the game and is hackable. Jim Ross and Jerry Lawler provide sporadic commentary while ring announcer Howard Finkel provided his voice for match introductions and wrestler entrances.
This is the first game to feature wrestlers on different brands, Raw and SmackDown!. In this game, all the wrestlers, including champions are eligible to be drafted on both brands, except for the WWE Undisputed Champion, who is available on both brands, as long as he is the champion. Scott Hall originally appeared as a member of the nWo. However, because of his release a few months earlier he was removed from the game, also Mick Foley and Bret Hart are not in the game but their created faces and features are. Tommy Dreamer, Justin Credible, Scott Hall, Bill DeMott, Mike Awesome, Chris Kanyon, Funaki, Jamie Noble and Chris Nowinski were scrapped from the game late but you can create them perfectly in the CAW mode. Shawn Michaels appears as a playable character in Exhibition mode and also can be used as a special referee but as an NPC for Season Mode. Vince McMahon, Ric Flair, and Stephanie McMahon are NPCs but can be played in special match types. This game marks the first appearance of former ECW and WCW wrestlers, as Vince McMahon purchased both companies in 2001. Superstars including Booker T, Rob Van Dam, Diamond Dallas Page, Lance Storm, Billy Kidman, Torrie Wilson, Stacy Keibler, Jazz, The Hurricane, and Chuck make their WWE video game debut. This game also marks the first appearance of John Cena, Randy Orton and Brock Lesnar as playable characters. This game is Jeff Hardy's last video game appearance until WWE SmackDown vs Raw 2008 in November 2007, as well as Mark Henry's last video game appearance until WWE SmackDown vs Raw 2007.