It was okay. The crate had me stumped for a bit until I clicked the sign on it. Likewise, four of runestones were easy to track down (and the Smart Thinker one was a nice touch!) but the last one didn't have much of an locator. I was pretty much clicking every object that wasn't a floor or wall, plus some bits of floor for good measure. It turned up eventually.
Apart from those snags, the rest went smoothly. A nice quick game!