Considering this thread is dead, double posts aren't that condemnable, right?
Well, 5 days later, I just killed Isaac for the first time. This is ridiculous, every time I think there is no way I can progress I get some insane combo that makes me invincible.
Both odd mushrooms, rock, pentagram, sacred heart and PHD that gave me several Tears Up pills made everything die instantly. Plus Super Meat Boy. And the relic and little CHAD just for good measure. I finished with full health and soul hearts that were still beyond the screen. Oh and I had unused 1up I got at the beginning of the game. Jesus.