I won't spoil the surprise, but suffice it to say it's a remarkable achievement in acting. Keeping Caveman short and sparse does not prevent Maxwell from exploring meaty issues. Despite his economy of words, his portraits of the three characters are remarkably vivid. He uses Pinteresque pauses to great effect, both comic and otherwise, and the whole enterprise is both interesting and entertaining. If the performance style of Caveman seems outside of the box, the production values are no less so.
More attention is paid to costumes, on the other hand.
In front of the stage, Maxwell has positioned the musicians on chairs that look like they might have been pulled from the dining room of the set. They sit with their backs to the audience. This is a good reminder of the final atypical feature of Maxwell's musical. Bereft of much of an overture, there is nonetheless a mini-concert after the show's curtain call. The night I attended, it was missed, alas, by most of the audience, which took it as a signal to head for the door.