Right, there are a number of differences between Red/Blue. The most well known differences are on the title screen and which Pokémon you can find. But there are other differences that need to be taken into account, like some palettes and the game corner prizes.
> Their decision to make two complementary games is really fascinating, especially from a business perspective.
Indeed. It seemed to be really successful especially given how small a development effort it apparently was. But why did no one but the Pokemon games seem to do it subsequently?
Someone's working on those differences here: http://romendo.net/stag019/pokedex/rbdiff/
Their decision to make two complementary games is really fascinating, especially from a business perspective.