I enjoy playing Dungeons of Dredmor quite a bit, and with the recent expansion my interest in the game has been rekindled. One thing that bugs more more than most in the game is that the base resolutions are fairly large. My monitor is fairly small, maxing at 1280x1024. This means that right now, if I wanted to play Dungeons of Dredmor and watch a stream of some other game like SC2 or LoL, Dungeons of Dredmor takes up roughly 60% of my screen real estate. Some other games, such as Dungeon Defenders allow for 640x480 or 800x600, both of which allow for better screen usage in windowed mode. tl;dr: I would like 640x480 or 800x600 resolution options, or a makeshift way to change the resolution besides the drop down menu through the launcher.
One particularly annoying thing about this otherwise largely well-sculpted game is that it covers up the toolbar on the bottom of the screen, causing me to not be able to view the clock and lose track of time quite easily, leading me to play far into the dark hours. To keep myself from turning into a Zomby, I sincerely hope more screen resolutions are introduced. I'm sure you're already working on it, given the existence of the resolution slider in the launcher.