Steven H. ported the game Open Transport Tycoon Deluxe, an open source clone of Chris Sawyer’s Transport Tycoon Deluxe to Dreamcast.

Release notes:

So, after a few grueling weeks of screwing around with the KOS libraries (KallistOS) I managed to compile and run the latest revision of OTTD.

It’s been more of an educational experience than anything else and runs like crap [at around 70% speed] (the 200mhz SH4 CPU seems to struggle) but it’s been a lot of fun…
I have CD images in DiscJuggler format (self-booting) of the latest version but due to dependencies that don’t exist off-the-shelf I don’t think this should ever be included in the trunk… I mean, does anyone still have DC with Mouse and Keyboard?

… on that note, the controller can be used… but it’s not as much fun.

http://dcemulation.org/phpBB/viewtopic.php?f=72&t=98191