Sonic Speed Simulator^{[lower-alpha 1]} is a massively multiplayer online incremental platform game developed and published by Gamefam Studios, under license and in association with Sega of America,^[1] and serves as an official entry in the Sonic the Hedgehog franchise on the gaming and game development platform Roblox. The gameplay involves moving around and collecting Chaos Orbs to level up and increase speed and jumping power.

The player walks around and collects Chaos Orbs and rings around a world (map). While walking around gives them XP, collecting Chaos Orbs gives more XP to help them level up, which then increases their speed and jumping power. The maximum XP earned per level increases with the level. Other ways to earn XP are by running and jumping through Sky Rings, completing quests and Time Trials (challenges that involve passing through spawned checkpoints and reaching the goal within a world as fast as possible), and buying from in-game shops. At any time, the player can rebirth, which resets the player's speed, power, and level, but returns Skill Points, which can be used to buy permanent upgrades.

Initially, the player's character is their Roblox avatar, but they can obtain Sonic characters to play as by completing Quests and limited-time event objectives, collecting cards,^[1][2][3][4] redeeming codes, and purchasing them for a limited time.

Trails and pets, which give upgradeable benefits,^[5][6] are obtained through spending rings on vending machines and completing Quests, event objectives, and Time Trials. Trails and pets can be leveled up at Upgrade Machines with rings, Red Star Rings, or both, and identical ones can be fused together into "Evolved" forms.

To unlock the next world, the player must earn five Gate Keys from Quests.

Sonic Speed Simulator was announced and released in closed beta on April 13, 2022, requiring 50 Robux for access to play, before being fully released as free to play three days later on April 16, 2022.^[7] The game had 70 million plays^[8] and 275,000 concurrent players in the first week of its release, which made its launch Roblox's largest. It went on to reach 500 million visits in its first four months. Joe Ferencz, the CEO of Gamefam Studios, described it as "the No. 1 branded game of all time on Roblox".^[9]

During the Sonic Central 2022 presentation shown on June 7, it was announced that a new area of Chemical Plant Zone would be released on June 11. Additionally, a code for the Amy Chao was unveiled and became available later that same day.^[10]

On February 26, 2023, a new feature was added to the game, known as "Auto Run", where the player automatically runs around the entire map, and collects rings and XP without any control over their character. Many players expressed disappointment with this update, citing the slower pace, not being able to jump or go side-to-side, and the rewards system as downsides.^[11]

On March 11, 2023, Shadow the Hedgehog was added to the game, with players have the opportunity to unlock the character during the Release Shadow event.^[12]

Alan Wen's review on Eurogamer was positive and praised the 3D, open-world gameplay, stating that Sonic Speed Simulator is "probably the most polished experience to have graced Roblox so far", but criticized the progression, obstacle courses, and race minigame, finding the progression to be unsatisfying and race minigame as too basic and lag-inducing.^[18]

• List of Sonic the Hedgehog video games
• List of Roblox games