To paraphrase Bill Murray’s character in Ghostbusters, here’s something you don’t see everyday: a side-scrolling shoot-‘em-up presented in the lovingly hand-drawn visual style of 1930s Max Fleischer cartoons. An unhinged fever dream in which Betty Boop is reimagined as a vindictive mermaid with an octopus sitting on top of her baby doll head, frogs in boxing gloves duke it out in a riverboat speakeasy to the manic strains of a hopped-up jazz soundtrack, and a sambaing screen-sized flower pelts its enemies with explosive carrots. This is just a taster – an amuse-bouche, if you will – of the consistently inventive and…