Here is a MAME demo recording of me finishing the game at 7-4 in one credit. Not the most perfectly played game, but I made it.
wboy-1474820-area7finish.zip (222k)
It was made with MAME32 v85. It should work with all versions from about v80 onwards, provided the romset is current (wboy.zip - set 1, new encryption). Note that earlier MAME versions used a different recording format, so it won't work with those.
Update: This doesn't work with v103, but you can get older versions of MAME at Joy Monkey. It works with v86, using the wboy.zip rom that was last updated in v34 (and is still current as of v103).