In this mode you play through all 23 stages (including The Last Way) in order starting from the top of the level select chart down. Alot 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 this mode so you can take your time. Also, no characters are running along side of you, therefore, you can defeat any or all the enemies and you won't be scolded for it. Also, there is no ranking.The beginning of every stage has a hint marker containing a message from a different character wishing you good luck and telling you 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.