A generic horror/pulp style setting, replete with atmosphere, a comprehensive backstory and filled with a whole bunch of details... what more could you ask for?
Zombies. Well, OK... read on!
The product opens with an extensive treatise on game mechanics, providing a basic skills system should your chosen ruleset not have a way of handling non-combat skills well and also conversion notes for a raft of different game mechanics. It may take a little work to get everything set up for the system that you use, but it's worth the effort.
Then we get on to the Tower itself. There's the comprehensive backstory I mentioned earlier which explains the story behind the tower and its current owner, and what is going on there. This begins to suggest reasons why the party might be interested in going there as well as setting the scene. The default genre is around late-Victorian era horror, classic Dracula/Frankenstein style, but it would not be too difficult to translate it to a more modern setting or even transplant it into your fantasy game (although you might want to alter the room descriptions or find a way of explaining the anachronisms).
Next the physical layout and contents are described in atmospheric detail, making it easy to describe to your players as they explore.... adventure enough can be deduced from reading these descriptions, but for added inspiration there is a collection of adventure seeds which will give you a starting point in deciding what will transpire here. Each takes a slightly different approach, so you may wish to choose the one most closely aligned with the precise genre of game you wish to play.
Finally there's a randomiser called the Cosmic Eye, designed to help you develop plot twists and answers pretty much on the fly. Some people like this sort of thing, others hate it; but it's there if you want to use it.
A well thought out and useful generic horror setting with the potential to create memorable and atmospheric adventures. And yes, zombies are indeed possible...