Most critics like it, with reservations. The praise clusters on the premise: a multiverse format that lets secondary Big Bang Theory characters lead their own adventure and gives the writers room for inventive scenarios, detailed alternate dimensions and meta jokes about the parent show. Several reviews single out the world-building and the comic chemistry of the central cast, and the general feeling is that it is bolder and nerdier than anyone expected from a spin-off.
The reservations are almost all about the jokes. Even admirers find the comedy uneven and only sporadically funny, and Collider notes the female characters are underserved and the emotional depth is limited. The spread is wide. The Telegraph finds the premise clever but the result irritating, and Vulture dissents outright, calling it painful, badly plotted and without stakes, an interesting idea let down by its execution. Five positive verdicts against one mixed and one negative, but the negative one is emphatic.