I like the idea of evolution simulation games, and I get a kick out of stuff like Conway's Game of Life. The ideas here are neat, but it's a little difficult to read the results of the different stats. For example, I don't know if the hypothetical religion starts at a single nation and then spreads (and if so, which does it start at?), or starts at all nations. The percentage breakdown helps, but is still a little confusing. Being able to define multiple religions, or nation-wide philosophies, and see how they compete would be really neat. It would also be interesting to modify more properties of religion e.g. consequences for apostasy, effects on class structure, severity of internal rules, extent of role in government, etc. All of that's outside the scope of 48 hours though.
I guess what I'm saying is that this is cool and has a lot of potential if you mean to keep working on it! Also, your game reminds me of a Richard Dawkins essay "Viruses of the Mind," worth checking out.