Did you know there are two PC versions of Sonic CD? Three if you count Origins, which I'm not? I mean you should do, it's been documented for a while, but I bet nobody has done this before: Sonic CD was released twice on PC, once in 1995, and again in 1996. The 1995 version was created in conjunction with Intel to prove a point about console games running on PC - it uses proprietary libraries (called "Dino") to get the job done, and was packaged exclusively as an OEM product with computers from Packard Bell and HP, etc. They say it's rare, but apparently they shifted at least 5 million copies, so maybe not. The second release was a stand-alone retail version which uses the de facto gaming standard at the time, DirectX. This is the version you've probably seen or played, since it was the basis for all the retail copies of the game and the version in Gems Collection. I've got an emulated Windows 95 PC which I set up to help Sega Retro. Today I installed both versions of Sonic CD on it. And while they're installed in different places and have been packaged up differently, unfortunately they detect each other and won't let me run them both at once. The Dino version has different credits (in the about window, not the game proper) but I wanted to see if there were any other obvious differences - whether it was hiding things that we might not know about, and for completion's sake. Most of the package is the same - they're both running Sonic CD, and the "game" part doesn't look as if it was altered. It's mostly changes to the menus, swapped out fonts in help files, and a general tightening up of the presentation (it's "SONIC CD" in the DirectX version instead of "Sonic Game"). The Dino version is also capped at 30FPS with no means of bumping it up to 60 - that's the number one reason not to care right there. It does, however, have a proper launcher with the Sega jingle on boot - the DirectX version defaults to one of those bog-standard blue background installer screens every time. What I hadn't expected was re-encoded video files. Neither are great - the game forces you to run in 256 colours and you still have to watch it through a little window, but the Dino version looks incorrectly scaled and has more visible artefacts in motion. But it might have better colours? These are both AVI files you can find on the disc, so it's not a Dino -> DirectX thing, they just replaced the files. The Sonic Boom theme is baked in for both, so it's not a localisation issue (I think Japan received the US soundtrack with this one). There's some other weird changes - default volume levels differ a bit, the Dino version can't mix samples together, so when you collect two rings in quick succession, the first sound is clipped out (especially noticeable when tallying up the scores). On this emulated machine loading times are about the same, but it's well in advance of minimum specs so that's perhaps not surprising. There are easily findable dumps on archive.org if you want to go hunting through the game's data, but for the two people who might care, confirmation they are noticeably different in places.