You cannot hurt the guards so you have to avoid them. They have senses of sight and hearing. You gain distance from pursuing guards by either leaping out of one-way windows, or cutting diagonally around corners. Guards cannot do either of those things.
I had a travel conflict the first part of the week so I started Wednesday morning and finished Sunday night. Because of the shortened schedule I used some existing stealth gameplay I’d developed previously and focused on two goals: coming up with a random level generator to support it, and doing some story-telling. I completely failed at the latter goal, but I did manage to come up with a reasonable level generator.
This game largely reuses code. The engine is shared with last year’s entry, Goblin Gold, and the dungeon generator started from one I’d developed when trying to come up with random starships. The gameplay came from ThiefRL; I stripped a lot of features out to try and streamline the game though. No lock-picking mini-game, for instance.