Sonic Before the Sequel

Sonic Before the Sequel is a Sonic the Hedgehog fangame made by LakeFeperd in the Sonic Worlds engine and released near the end of 2011.

It begins just after the end of Sonic 1, when the Chaos Emeralds suddenly teleport Sonic to a place where he can see Dr. Eggman's Death Egg being built far away. Sonic sets out to stop Eggman's plans (while stupidly ignoring the seventh emerald by his side) and later meets Tails, who is eager to help him.

Download the game and have fun.^{[dead link]}

A sequel named Sonic After The Sequel is already in the works.^{[dead link]}

Tropes used in Sonic Before the Sequel include:

Advancing Boss of Doom: Eggman's machines in Hilltop Heights and Titanic Tower.
Behind the Black: In the opening scene, Sonic notices the Death Egg faaaaar away in the background, but ignores the seventh Chaos Emerald that was a couple feet away from him, hidden by the camera.
Blackout Basement: Parts of Acts 2 and 3 of Titanic Tower Zone.
Bonus Boss: A Mecha Sonic that was cut from the normal game appears in the Boss Rush.
Bonus Level: Can be entered from the third act of each zone. They're called Special Stages as per series tradition, but they're inconsequential and just for racking up extra lives.
Boss Rush: Available after beating the game with the good ending.
Bubbly Clouds: Cloudy Crowd Zone.
Double Jump: The Bubble Shield in Fortress Flow Zone allows Sonic to Double Jump.
Foregone Conclusion: Sonic can't stop the launch of the Death Egg. Well, he can in the Boss Rush, but that's just a "FAKE END".
Heads I Win, Tails You Lose: After being defeated, the Final Boss simply blasts Sonic out of the sky in the ending cutscene.
Hero of Another Story: Sonic and Tails spend the game alternating zones between them, so technically they're both on their own solo adventures, even when their paths cross in the latter half of the game. The only stage played by both of them is Arcane Altitude Zone.
Interface Screw: Fuzzies inexplicably show up throughout Star Shores Zone.
Interquel
Multiple Endings: A "Good" Ending and a Bad Ending. The Boss Rush also has a unique ending.
- Word of God has confirmed there will be five endings in After The Sequel. The Time Point Ending, for finishing with enough Time Points, which works the same as in Before The Sequel. Thre is the Chaos Emerald ending, for collecting all the Chaos Emeralds. The good ending, for doing both of these things, and the bad ending, for failing both of them. The fifth ending has not been confirmed yet however, presumably it's a Boss Rush ending like in Before The Sequel.
Recycled Soundtrack: The entire soundtrack reuses songs ranging from other Sonic games to Kirby games. The 2012 SAGE edition will avert this with an original soundtrack. Two songs from the new soundtrack were already released by the composer: "Rivulets" and "Friday Purples".
Shout-Out: Ryu Turtle Badniks?
Super Mode: Available as an Easter Egg. S Monitors are hidden in the levels and pressing a certain key in the full main menu unlocks Super Sonic.
Super Not-Drowning Skills: Fortress Flow Zone, in which Sonic gets a water shield that's immune to damage. Instead, you lose your rings when you're hit.
- Super Drowning Skills: No such luck for Tails, who must scrounge for air bubbles in Perilous Paradise Zone.
Timed Mission: You have about a hour and a half to beat the game, or the bad ending happens when you get there.
- Specifically, you start the game with 3400 "Time Points", you lose one every 2 seconds, and if your Time Points are a negative value after the final boss, you miss the good ending.

Word of God has confirmed that After the Sequel will be this as well.

Under the Sea: Fortress Flow Zone.