Update []:
We reported on Sonic Mania's Dreamcast port a while back, and since then, the developers behind this unofficial effort have been polishing it even further.
The game now has audio, and one of the team members, falco_girgis, is even going the extra mile to replicate the complex 3D bonus stages on Sega's last home console.
It hasn't been an easy process, and at one point, the team almost gave up on incorporating them, but a solution has been found:
"We already moved all 2D and 3D rendering to the DC's PowerVR GPU, which can push a bazillion times as many polygons as the 3D stages use, so there should be no problem handling them, riiiiight?
NOPE. It's not that easy! Our poor SH4 CPU is now being absolutely murdered and under-utilized due to the fact that all of the matrix and vector math for the 3D graphics transforms has been implemented using FIXED POINT INTEGER OPERATIONS... which means the SH4 doesn't get to utilize its baller FPU or special vector instructions that are responsible for accelerating this kind of math... and more importantly, it means none of these structures are compatible with my SH4ZAM linear algebra library we use to accelerate math for gainz on most of our Dreamcast ports...
So after wallowing in self-defeat for a few hours and questioning whether it was even possible to accelerate this shit reasonably... I came up with what I think is an ingenious solution.
We're going to replace the original Matrix struct containing a 4x4 array of fixed-point int32_t entries with some crazy, newfangled C++23-based abomination that leverages some questionable and evil language features, allowing it to be represented as a 4x4 array of floats internally... and we're going to do it noninvasively, so that the rest of the game and engine code, which operates on fixed-point integers, will still continue to work properly without needing to change a line of client code... SO LETS DO IT!"
Original Story []: Sonic Mania caused quite a sensation when it arrived a few years ago.
A love letter to 2D Sonic developed by fans but with Sega's blessing, it ended up putting other, modern Sonic titles to shame – so it's little wonder that people are still keen to play it on as many platforms as possible, even today.
SonicFreak94 announced some time ago the intention to port the game to Dreamcast, and the project has been developing at quite a brisk pace of late. We now have footage of the game running on real hardware, and it's looking utterly brilliant, as you can see:
All of the stages are now playable, and the game runs at a smooth 60 FPS.
In a really cool twist, one fan has also mocked up (unofficial) packaging for the game, which really does make it feel like the "lost" Dreamcast classic we never got: