Gameplay involves controlling Sonic around with the Wii Remote's motion-sensing functionality, particularly swinging around the sword to attack enemies and to move forward.

Reviewers praised the graphics, presentation, story, and large amounts of bonus content, but criticized the controls, swordplay mechanics, and multiplayer aspects.

[8][9] Beating stages with a higher rank gives the player better rewards,[6] which can be brought to the blacksmith (Tails) to create new, or upgrade old equipment.

[9] Each has their own characteristics; for instance, Knuckles wields dual swords that double as boomerangs and has the ability to glide, Blaze can surround herself with fire and use more lunge attacks than Sonic, and Shadow can use Chaos Powers.

After completing her tasks, Nimue tells him that he must collect the other sacred swords wielded by Lancelot, Gawain, and Percival of the Round Table in order to dispel the immortality granted by Excalibur's scabbard.

However, her plan is completely flawed, as such a world, going against the natural order of things, would not function properly, and it would come at the cost of innocent lives.

In a post-credits cutscene, Sonic returns to his world and tells Amy about his adventures, but she believes it to be an excuse for missing their planned date.

Since the franchise's demographic largely consisted of children, it was decided that the sequel would focus on that demographic to boost sales; the decision to base the story on Knights of the Round Table was decided on due to wanting to attract new players to both the series and the legend, noting how it had previously influenced the Star Wars franchise.

[10] In comparison Sonic Unleashed (2008), which was level design-oriented, Black Knight focused on the combat and cinematic presentation.

[11] During early development, Sega held focus testing in the U.S. to choose the most popular characters from the legend to be used in-game, with the artists adding various attributes of knights to their appearance.

[10] Sonic and the Black Knight was revealed on July 21, 2008, at Nintendo's pre-Tokyo Game Show (TGS) 2008 press conference.

[8] In August 2008, Sega held a contest where fans could submit illustrations, of which 20 would be included in the game's gallery;[10][14][15] shortly after release, however, it was discovered one of the winners had plagiarised from another artist.

[20][21][22] The other album, Tales of Knighthood: Sonic and the Black Knight Original Soundtrax featured the rest of the game's soundtrack spread across two discs.

[40][41][42] IGN's Matt Casamassina praised the game's visuals and the overall presentation, but went on to state that the gameplay was "broken" and cited the controls as "unresponsive".

"[35] Chris Scullion from the UK's Official Nintendo Magazine praised the game's visuals and soundtrack, but criticized the swordplay mechanics and multiplayer element.