The phrase "lava levels" refers to the different heights or amounts of molten rock, called lava, within a volcano or a volcanic eruption. Full definition
There's also a pretty cool like Dry Bones coaster platform you can ride in lava levels, which reminds me an awful lot of both the Bonecoasters in New Super Mario Bros Wii and the raft riding in Super Mario 3D Land's final level. (gamingreinvented.com)
While the level design is a little expected in terms of visuals (ice level lava level mushroom level!) (darkstation.com)
Gourmand Land takes food as its theme, effortlessly spinning snowy freezer cabinets and lava levels inside an oven. (pcgamer.com)