Very simple paint program. You can just move a point to trace some patterns or turn into erase mode by pressing a key. Trace or erase, that's all you can do.

Maybe it was impressive to be able to paint some stuff on TV screen in 1977 though.

But it is obvious that Doodle is a poor copy of the Doodle game for the Fairchild Channel F, released on year earlier (1976) and in color!