Recent reviews by Dire, Dire Docs

It might not be as polished or packed-to-the brim as the remake is, but the original Binding of Isaac still holds up perfectly. It's arguably just as good as the remake as well, despite the lack of polish, as the game's smaller item pool actually gives you a better chance to have a decent build every run.
While you don't have to play the original in order to fully appreciate the remake, I'd still highly recommend it. Completing the game is 100% worth it.
Apart from hard mode.
Don't touch hard mode.