The title says it: You are in a dark cell, having been captured by guards, and must escape it.
As far as difficulty, it's not too hard. My first try I got out in about 100 moves. There were some minor nitpicks with the parser, and one of the puzzles, but not much.
(Spoiler - click to show) You pick the lock, but can't open the door, something else is holding the door shut. Part of the puzzle is learning what that is. There is another cell with a prisoner opposite you. It seems like you could just look at HIS door to see what the problem is, but the game doesn't recognise his door. Further, you can't seem to ask the other prisoner about the bolt, you need to see it yourself. You also must use "GIVE [x] to [person]" instead of "THROW [x] to [person]"
The writing is appropriate, I noticed no glaring errors.
Now the puzzle itself is beautiful. Unfortunately, because of the nature of the puzzles, I can't say too much about them without giving something away, but suffice to say it isn't quite as easy as using your lockpicks to get out. (Though lighting up the room is very easy and straightforward). The game does provide a false hint. (Spoiler - click to show) It suggests making a projectile to share items with the other prisoner, though no projectile is needed, you merely tie items up for safety and throw them, which had me wasting time trying to make a slingshot or something . I'll be fair and say I'm generally not a fan of IF escape games: I've played plenty of flash based ones that were garbage, and plenty of text ones seem to involve trite tropes or nonsensical scenarios, but this one makes even the done-to-death escape a jail cell fun.
Once you escape the cell the game ends, though the endstory makes reference to the need to get past the guards and steal horses. It would have been nice to see this part of the story (either as part of this game or as a sequel).
In conclusion, the scenario is trite, but that was the contest: a one room escape game. And the author did this one beautifully.