Expert Mode is an unlockable gameplay mode in Shadow the Hedgehog where the player has to play through all Stages in the game in order to complete it. Supposedly, it is a form of training that Shadow goes through and is to be a true test of Shadow's skills. Expert Mode can only be unlocked in the gmae by attaining an A-rank on every single stage in the game.
In Expert Mode, the player plays through all 23 stages (including The Last Way) available in Shadow the Hedgehog in order, starting from the top of the level select chart down. Many of the first stages are nearly the same, just a few extra platforms and some more rings to use Light Speed Dash. There are no specific objectives in Expert Mode, no characters are running alongside the player and there is not given a rank after completing a stage. The beginning of every stage has a hint marker containing a message from a different character wishing Shadow good luck and telling the player how Expert Mode works. The final hint marker at the beginning of The Last Way gives luck from every single character seen in the game.
- In The Doom version of Expert Mode, it is the same as the Hero mission, except that the researchers are all in one room at the end, right beside a Heal Unit spawn.
- Other characters from the game including Cheese and Cream (even though they were only an objective in Cryptic Castle), Gerald Robotnik, the GUN Commander, and even the President show up as hint characters.
- Important and sometimes interesting information is often revealed by the hints at the start of each level in Expert Mode. Aside from the objective of each level, personal information from the speaker is sometimes revealed such as the Commander's new grandchild or the reason for the hostile actions of the Artificial Chaos.