"cosedit"  seems to be a  DOS-based  GUI that can  edit levels for the
game  "Cosmo's Cosmic Adventure"  (also known as  "Forbidden Planet").
This program hasn't been tested locally.

Notes from a related web site:

"This  is the  first  graphical level editor  for Cosmo.  It's a fully
functional and pretty easy to use DOS editor, although  it appears  to
have a bug with a sprite limit and not reading the bottom row of tiles
in a level properly.  It's still in  a usable condition  however,  and
it's definitely  the best choice when it  comes to  editing  Cosmo le-
vels."