Rock-paper-scissors decides whether Tokyo survives the night. A man armed with nothing but the world's most basic game and absolute confidence fights giant monsters on live television in front of millions. It is exactly as stupid and exactly as committed as it sounds, and that commitment is the whole thing. The OVA knows the premise is one joke stretched to its absolute limit, so it plants itself there and refuses to blink. You're either laughing at the sincerity of a man who will solve every problem by throwing a hand sign at a kaiju, or you're not watching Jankenman. This is not a show with a deeper layer waiting underneath. The joke is the thing, executed with the straightforward clarity of a 1992 studio that decided to make one joke once and make it count.
Jankenman: Kaijuu Dai Kessen is a 1992 comedy OVA from Ashi Productions.