A while ago I said Sonic Colors is running on the Hedgehog Engine. So, here's a thread with some technical details about the game and it's engine.

First of all, Hedgehog Engine is a game engine, not a graphics engine. There are many parts to it, a few being: Universe (Actor library), Mirage (Graphics engine), Sparkle (Particle engine, replaced since LW), Database (Filesystem library, replaced since LW).

When Colors was in development Sonic Team started refactoring parts of the engine for more flexibility. The engine was slightly refactored during LW's development, then during Forces' development they re-wrote the graphical part of the engine, and slightly refactored other parts.

Now for the more technical parts, Colors and Lost World share a lot of code. For instance, the Universe library and the set object manager is pretty much the same, screenshots below. Some arguments appear incorrect because of the decompiler.

Colors also uses the Database library mentioned earlier, Suggesting the game used Hedgehog Engine. The Database library has been in use since Unleashed and later replaced in Lost World.

More on code sharing, Lost World and Colors share classes with same names and functions, Although there aren't many names available in Colors' executable there is still enough to suggest that the game uses Hedgehog Engine.

Throughout this thread I've been comparing Colors a lot to Lost World, what's up with that? Lost World was built on top of Colors. There are many source paths still present in the Wii U version of Lost World that mention Sonic2010 (Internal name for Colors).

The build path for Lost World PC mentions Sonic2010. Here's a small part of it "C:\\build\\SLW\\Sonic2010\\b..". Which then led me to investigate Colors and find about the similarities. If anyone wants to investigate further into Colors here is my IDA database https://mega.nz/file/coxhxKhB#aT2ZVHZwXTi62YbaT0pyeqAt26mwMh3ldo1Gkjw4sgw