CorsixTH is the wonderful free and open source game engine for Theme Hospital, featuring plenty of improvements and modern system support.
After a relatively short testing period for the Release Candidates and a year since the last full update, CorsixTH 0.64 has been released. This release comes with the ability to use ISO images of the original discs as a data source, since CorsixTH requires the original data files. With this release the UI was updated to be sized properly in all languages, Level 6 map issues were solved, rooms becoming stuck should no longer be an issue, potential memory leaks solved and a lot more done over the last year.
So what's the point in playing Theme Hospital in CorsixTH? Higher resolution support, bug fixes, quality of life improvements to various places and the list goes on. With it being open source, it means anyone can come along and fix issues or add new features too. They have a TODO list here if you're interesting.
Just like other excellent FOSS game engines openXcom (UFO: Enemy Unknown), OpenMW (Morrowind - which just had an update recently) 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.