I think this program is not really running on an Odyssey2 console or emulator. I think someone has just made something for a different computer or console which looks like the Odyssey2 character set.
After a bit of searching I found the code (with source) at http://www.pouet.net/prod.php?which=55255
. It is Videopac code, but only runs on o2em. On a real machine there is a gap in the top half where the gfx are off and you see the usual distortions when overlapping chars.