Riding a wave of goodwill after the warm reception of their first two shows, this sketch duo’s next outing feels purpose-built to outdo its predecessors, perhaps to a fault. Eyes Closed, Mouths Open finds Sullivan Brown and Rosie Nicholls trapped in a bunker after a catastrophic event. All they have to while away the hours are a co-dependent relationship, clothes they’ve stolen from dead people, and a desire to act out comic sketches for an imaginary audience.  

From this gracefully dark framing device the pair veer between gentle absurdity, rapid-fire dialogue, striking set design and sharp left turns into drama. Whether they’re lining their sights on oversized owls or speculating about aliens who can’t digest dairy, there’s an obsessive desire here to elongate sketches beyond simple skits, revisiting characters and incorporating them into a larger story. Each sketch is pitched with a meticulous eye from Brown and Nicholls, whose range and zippy chemistry could make them household names with the right vehicle (honestly, chuck these sketch comics into a serious prestige drama and they’d soar). 

Satisfying though their many third-act pay-offs are, it’s a strangely backloaded show, all set up in the opening 30 minutes without much bite. When the laughs do come (along with a beautifully written elongated meet-cute sequence towards the finale), they arrive in waves of callbacks and accumulations, with an intricate and impressive closer. It takes too long to hit a sweet spot and suffers from a surfeit of ambition, but the best bits on display here illustrate why Grubby Little Mitts are hotly tipped. 

Grubby Little Mitts: Eyes Closed, Mouths Open, Assembly George Square Studios, until 26 August, 4.35pm; picture: Dylan Woodley.