Citadel of Blood is an enjoyable and immersive solitaire dungeon crawler from the 1980s with some of the elements of a wargame. The exploration is completely random---you are drawing chits from a cup to build the map---and poor draws will dramatically alter the length of play: I once drew 40 chits (read: took forty turns) before getting the mirror and stairwell required to leave the first floor.*
The rooms in this citadel are far more varied than I'd expected for a game like this. Furniture, art, fountains, chests, monsters, and many other things are encountered, and each of these has 6 or more possibilities (many more in the case of the monsters), so there are upwards of 60 things the party might come across every move.
The battles are better handled than in something like Barbarian Prince: The player's party/combatants are arranged in ranks as are the enemies, which sets the groundwork for a less abstracted battle than is usually found in fantasy boardgames. Special abilities also detail things nicely, and the two ways to opt out of a battle---through negotiation and (failing that) monster bribery---are great touches.
There are a lot of charts to look up and the chits are tiny, so the imagery lives in your mind far more than on the table, but Citadel of Blood does what it sets out to do, and does so with a fun personality.
(*The 30 minute play time listed as typical on Boardgamegeek is wildly inaccurate unless you do terribly or are amazingly lucky. Even if you've internalized all of the charts--and this is a 1980s chit game, so that's unlikely--getting drawn into 5 or 6 bigger combat situations will take up that time.)