Yes, because I manually expanded various arrays to support that particular resolution, but not any larger ones. The primary offenders are textured backgrounds, ambient lighting, water, and the main menu screens, as well as the code for figuring out in general which tiles should be drawn on screen. An in-progress build was more flexible and (if you disabled the first three things) supported any resolution your monitor would—I've got various 1366x768 screenshots sitting around—but it had issues with FPS and general atmosphere. 800x600 was chosen.