dbg:*debug-print-level* controls the depth to which nested objects are printed during output from the debugger. If its value is a positive integer then components at or above that level are printed. By definition an object to be printed is considered to be at level 0, its components are at level 1, their subcomponents are at level 2, and so on. If
nil then objects are printed to arbitrary depth.
USER 89 > (setq dbg:*debug-print-level* 2)
Type :c followed by a number to proceed
LispWorks User Guide and Reference Manual - 13 Feb 2015