I've isolated the problem to the hard drive. In the meantime I've been doing some thinking about the overall project I've been working on.
I've been contemplating two large changes to my thief-like/rogue-like. The first is random level generation. Before the computer crash I was working on a prototype for generating a full city. I envision the city as consisting of several large compounds which are the focus for thieving missions, surrounded by houses, shops, and so forth.
The main thing to consider with this is what gameplay purpose all the embedding city will serve. I run the risk of having large useless tracts of homes that just create unwanted travel time; or perhaps a level that will take too long to complete.
One idea I might try out is to have a kind of “inverse collectible”. I've been thinking about making gold into an actual currency rather than a strict collectible. In that case, I need places to spend gold. Taverns are an obvious thing. I was also thinking about having a “Robin Hood” style situation where you can distribute gold to the smaller homes. Perhaps homes would have little shrines into which you could deposit gold.
This opens up a lot of design issues. Can you retrieve the gold later? How does this change the main character's motivations? Do you get any sort of reward for doing this? I'm not convinced it's a good idea yet.
The other major feature I've been considering for the game is sidekicks. This could obviously be another gold sink. It might also help with the “heist” feel as you would need to plan out an operation ahead of time. This amounts to a whole new user interface element in the game, though; plus I would need to create the AI for the characters. So I'm trying to decide whether it would be an effective part of the game. One of my worries is that the AI characters would do interesting things that should properly be done by the player for maximum entertainment. Ideally they would either do things that the player can't do himself, or would allow tactics that aren't possible solo, or would make boring things less boring.
The Fire Emblem series of games (or perhaps Baldur's Gate) are a pretty good model of how I would envision sidekick characters interacting with each other. Basically there are little plot threads involving pairs (or in rare cases large configurations) of characters; if you have the proper character set assembled for a mission, another bit of that plot thread plays out. Sidekicks would also have plot threads that tied each of them to the central villain in some way, to help keep the player's focus on him.