Unlike a lot of platformer games that tend to be a little more forgiving in their pacing, the Sonic franchise has always been characterized by high-speed gameplay, which requires a tremendous amount of patience and skill from the player to be able to complete each and every stage they encounter through the games.
Some Sonic games that have been released over the years have made a real effort to be as accessible as possible by cutting down their difficulty, while others elevate the challenge even more to keep the gameplay fast and fun, so long as the player is able to keep up with Sonic's speed. In truth, it is the added difficulty of these games that sets Sonic apart from its competition, often being viewed as a much more skillful platformer that forces the players to master the physics of the game to successfully guide the Blue Blur to the end of a stage.
Sometimes, this challenge can lead to a lot of frustration, especially if it wasn't intentional and is due to faulty game mechanics that have been implemented, but for many die-hard fans, this simply makes achieving that 100% completion all the more satisfying.
9 Sonic Rush
The Nintendo DS title Sonic Rush was actually the first game in the series to introduce the controversial Boost mechanic where Sonic would accelerate at lightning speeds with just the press of a button. If players relied on this too heavily though, they could easily fall down a pit or even fly off the map entirely on some of the trickier stages like Altitude Limit.
Pair this with some of the toughest boss fights in the series that can strip Sonic of all his lives in little to no time, and some very challenging special stages that are needed for 100% completion, and it results in a decently challenging experience that players can only overcome by mastering the new Boost feature.
8 Shadow The Hedgehog
Alongside the darker and more serious tone of Shadow The Hedgehog also came some of the most punishing enemies and stages in the series. Unlike Sonic, who usually only uses his homing attack to take down enemies, Shadow is equipped with multiple guns and unique weapons to navigate the multi-branching story of his standalone game.
Despite being more powerful than his rival, the lack of an aiming system and an in-game map, alongside enemies who can easily stun-lock Shadow by repeatedly knocking him over like the GUN Troopers, make the game more difficult than it needs to be, especially when trying to unlock the ten endings.
7 Sonic Heroes
Developed during the very awkward transition from 2D to 3D Sonic games, it's immediately apparent when playing Sonic Heroes that Sonic Team had a lot of trouble mixing high-speed action with a 3D platform design, resulting in many of the characters slipping and sliding across each stage with no real direction.
This issue becomes even worse when players reach stages like Frog Forest and Rail Canyon where perfect timing and precise movements are required to navigate towards the end. Sonic Heroes was undoubtedly a huge step forward in the era of modern Sonic games, but completing the story with all four teams can still be an arduous task due to the unpredictable controls.
6 Sonic Adventure 2
Running through the brilliantly told main story of Sonic Adventure 2 isn't too difficult, but the true challenge comes from trying to 100% the game by acquiring an A rank on every stage. The shooting and hunting stages are already difficult enough, but the speed stages really take the challenge to a whole new level, with levels like Pyramid Cave forcing the player to jump through hoops and take down each enemy they find, all while keeping track of their time.
The unlockable 3D Green Hills stage is definitely a nice reward for acquiring all 180 Emblems, but only the most hardened Sonic fans have ever been able to achieve this challenging feat.
5 Sonic 2
The first playthrough of Sonic 2 can be a grueling one, with stages like Metropolis Zone and even Chemical Plant Zone testing the player's mastery of the physics in the game, along with a final boss that many fans agree is the toughest last encounter in the entire series.
Sonic 2 knows that it's a challenging experience, and because of this, it does throw a few lifelines out to the player such as the 1-ups that are scattered through the stages, but it is still undoubtedly one of the most challenging entries, which becomes even harder when using Sonic and Tails simultaneously.
4 Sonic CD
Nearly all of Sonic CD's stages require the player to memorize the layout like the back of their hand if they want any chance of completing the level with a good time. The stages themselves are much trickier to navigate than other games of the classic era, and the time travel gimmick only helps to make them even harder.
To complete a stage, players will need to search for time travel spots, seek out the Metal Sonic holograms, and still finish the level with at least 50 rings, but considering the very demanding time limits and the number of badniks and spikes scattered across each stage, this can all be too much to manage for many players.
3 Sonic The Hedgehog (2006)
The most infamous Sonic game ever released, Sonic The Hedgehog (2006) is similar to Sonic Heroes in how its unpredictable movement and overall jankiness can make it a lot harder to play than it should be, but the difference is this lasts throughout the entire game of rather than just spiking the challenge at certain moments.
Sonic can easily fall to his death in stages like Crisis City and Radical Train if moving just a little too fast, while the Silver missions can become a real chore due to the clunky psychic abilities that are needed to complete certain levels. Silver's boss fight is an especially frustrating part of the game where random boxes can land on Sonic, removing all of his rings in an instant.
While not intended to be as difficult as it is, the rushed development and unrefined movement and mechanics of Sonic The Hedgehog make it a real test of patience for those who play it.
2 Sonic Spinball
Pinball has always been very closely related to the Sonic games, with some titles like Sonic Heroes designing entire levels around it, but Sonic Spinball on the Sega Genesis had the mechanic in mind when the game was being developed, with Sonic curling up and acting as a pinball for a lot of the levels.
The goal of each stage is to collect all the Chaos Emeralds, but the blistering speed Sonic travels at when flicked, and the way he bounces off walls so randomly makes this much easier said than done. It might be incredibly short, but it's also a game that requires a lot of patience and pinpoint precision, which can be very tricky to get the hang of until players have at least a few playthroughs under their belt.
1 Sonic Unleashed
In a time when Sonic fans were starting to become bored with released titles that were too easy to play and complete, Sonic Unleashed provided the perfect challenge that very rarely became frustrating, but always kept the player on their toes both when playing as normal Sonic in the day stages and as the Werehog at night.
To achieve a decent rank in the day stages, players would need to run through them over and over again to collect medals and score a perfect time, and as for the Werehog, they would be required to hack and slash their way through hordes of spongy enemies, who at times would become ridiculously strong, such as on potentially the hardest level in the entire series, Eggmanland. Rather than simply completing a level to move on, Sonic also needed to collect a certain number of medals before he could advance, which made achieving 100% completion an extremely difficult task.