Create a floor filled with hatches on a very high z level that covers your embark. Link all hatches to levers in a control room of doom somewhere. Pump magma up from the magma sea. Laugh manically when you flood the surface with magma :) (and destroy your FPS...)

Not sure about LBP as I haven't played it. I was hoping wikipedia would have a list of Turing-complete games but I can't find one.