This game is pretty good! Under normal circumstances, I would also say I really like how the text and game over screen look. However, I don't think transparency (as seen in the font and the game over screen) was possible on the Intellivision? I may be wrong, however.
Sounds good. I don't know how strict the rules are going to be on the font. I am just trying to be as safe as I can. Perhaps try the 10 size Trebuchet MS font I mention in my comment below? It isn't completely accurate to the Intellivision, but it looks fairly close to me. I'm not sure if Unity will actually lower the resolution when setting the size of the font down like GameMaker does, however.
The closest I could find (as far as common fonts go) to the original Intellivision font was using Trebuchet MS and setting the size to 10 (to lower the resolution) and turning off anti-aliasing. There may be other potential choices as well (including downloading the actual Intellivision fonts). I wasn't able to find any way to download the actual Intellivision font without registering with a new art website.