The gameplay in Underground 2 is similar to that of previous Tony Hawk games: the player skates around in a 3D environment modeled after various cities and attempts to complete various goals. Most goals involve skating on or over various objects or performing combos. Scores are calculated by adding the sum of the point value of each trick strung together in a combo and then multiplying by the number of tricks in the combo. New gameplay features include the Focus ability, which the player may trigger with a full Special gauge to cause time to slow down in order to help keep up their combo (by allowing greater control of their grind balance, for example); the Natas Spin, which can be performed on small surfaces like pillars or fire hydrants; and the Freak Out, which serves as another combo starter by having the player fill a gauge after certain bails, which will result in them angrily disposing of their board before continuing their session. In addition, the Wallplant maneuver was repurposed as the Sticker Slap.
Many levels return from previous games, including an expanded Warehouse (which also serves as the Story Mode's training area), School and Downhill Jam from Tony Hawk's Pro Skater, Philadelphia from Pro Skater 2, and Canada, Los Angeles and Airport from Pro Skater 3.