In the source engine at least, you can playback recorded gameplay at arbitrary timescales, and at one point I had it play back a scenario at several hundred FPS

In the source engine at least, you can playback recorded gameplay at arbitrary timescales, and at one point I had it play back a scenario at several hundred FPS equivalent and used some virtualdub plugin to merge batches of frames, and indeed the footage looked much more continuous than just a single, infinitely fast exposure per displayed frame.