What game from a developer came completely out of left field?

Take Croteam for example. Though they made a few games before Serious Sam, it was that game and subsequent series that got them known. From out of seeming nowhere then, we get Talos Principle from them.

To go from a fairly mindless, though fun, FPS series, with a very heavy emphasis on shooter, to a thought provoking first-person puzzler took me by suprise.

Anyone else got that kind of surprise from a developer?