A recent press conference for Sega and Rovio reveals that the 3D platformer sold 300,000 more units after its last milestone.
The open world platformer is continuing to sell at a decent rate, having hit 3 million units a little over a month ago.
The classic version of Amy is playable in four titles, while Knuckles is available on Sonic CD. Base game owners can upgrade for $9.99.
Race or fight to beat the clock in new Challenge Modes, listen to songs while exploring and capture stylish photos of Sonic in the update.
The 3D platformer, which uses new open zone mechanics, is available for Xbox One, Xbox Series X/S, PS4, PS5, PC, and Nintendo Switch.
Cyber Space Challenge and Battle Rush offer Time Attack and combat challenges, while Jukebox has 53 songs to listen to while exploring.
The first free content update adds the Juke Box, Photo Mode and new Challenge Modes. Two more updates are coming later this year.
"We will continue to sell over the long term based on sales strategies such as pricing, promotions, and the development of further DLC," Sega says.
Despite the success of the latest 3D Sonic in the form of Sonic Frontiers, we might also get more 2D Sonic games down the line.
Sega's most recent earnings report indicates that Sonic Frontiers has been quite a successful release and continues to enjoy sustained sales.
Sonic Team's Morio Kishimoto says he is thinking of making the next Sonic game more like Sonic Adventure.
If you're curious about how well Sonic Frontiers plays on the Nintendo Switch, its Japan-exclusive demo is now available on the eShop worldwide.
Though it doesn't provide any gameplay benefits, the free cosmetic suit adds a little Christmas flair to Sonic's get-up.
The "open zone" 3D platformer is available for Xbox One, Xbox Series X/S, PS4, PS5, PC, and Nintendo Switch, with more content coming in 2023.
Sega has revealed the first details on Sonic Frontiers' post-launch content, which will come in three waves across 2023.
Performance Mode is now available on Xbox Series S to prioritize frame rate after an issue prevented it from being available.
Takashi Iizuka also praises writer Ian Flynn. "He knows the characters well and brought great development to their emotions and interactions."
Sega has released a new update for its recently-released open world platformer, which looks to sand out some of the experience's rougher edges.
God of War Ragnarok dropped to fourth place and Sonic Frontiers to tenth place, with sales declining week-on-week for both.
Here's how to complete all of the Challenges throughout Starfall Island, and locate the different Portals leading to Cyber Space.