CorsixTH is a brilliant free and open source game engine for Theme Hospital, enabling it to play smoothly on modern systems and other improvements. Theme Hospital is a true classic, one that absolutely should be kept alive. I may be a little biased there though, as it was a game I played a great many hours of in my youth.
It's been over a year since the last CorsixTH release but it's coming soon! CorsixTH 0.64 has a first Release Candidate now up and in need of some testing. A big new experimental feature landed enabling ISO images of the game to be used as a data source. In addition many game bugs have been fixed, multiple of which were somewhat game-breaking with rooms being stuck and level errors. Memory leaks were also plugged up, some UI elements are now sized properly in all languages and Epidemic patients previously couldn't be treated while they were seeking a room.
There's just the icing, a lot more bugs were solved over the past year to make playing Theme Hospital with CorsixTH better than ever. Like other excellent FOSS game engines openXcom (UFO: Enemy Unknown), OpenMW (Morrowind) and more it does require you have the data files which you can grab easily on GOG.com.
Find out more about CorsixTH on the GitHub.