Lords of Chaos is an awesome little game, ripe for RPG Codex 'Discussion' because you create a wizard who levels up, and you get to control his stat and spell progression.
As
Jarpie mentioned the 8-bit and 16-bit versions differ, with the single biggest difference being in the fifth scenario (the tomb). Another notable (read: almost game-breaking) difference is that Giant Bats can carry things in the 16-bit versions, but not in the 8-bit versions. With the ability to fly great distances Giant Bats are quintessential scouts in open-aired maps, but the addition of an inventory makes them outright broken.
The retail release only had three scenarios, of which one is single-player only. An expansion pack was released with another two scenarios, but again one of them is single-player only. If that is not enough LoC-action, there's an exclusive covertape-released scenario available on the C-64 called 'Escape from Zol', which has elements from the first and third scenarios of the full game. It's single-player only sadly and you can't transfer the wizard onto other scenarios, but it was only meant to be a demo after all.
LoC is a game that had great potential which I felt was never actualized in its lifetime. If only a level editor had been released for it...