From the same publisher is the earlier Penumbra series, anyone who's only played Amnesia should definitely play those too. My favorite was the second one, Black Plague, and I think for all that Amnesia does right, Black Plague does it better. (I think it was even in one of the Bundles before but I'm not sure.) Amnesia has gained a lot of traction with the modders, though, and it's sometimes interesting to see what other people cook up. (The mods tend to rely too much on "jump scares" however, just like pretty much everyone else besides Frictional Games. They do it too, just not as much.)