Once the variety turns to tedium, and the humor becomes overused and grating, there is little left but the image of poop
The entire game is simply a side project for a developer behind Super Meat Boy, and feels a lot like an exercise in experimenting with coding. While it is priced appropriately for a side project, at a cheap five dollars, the ultimate problem is it is not even worth your time.
The Binding of Isaac is a dungeon-crawler with many action game elements. The entire game takes place from top-down perspective in square rooms, connected to other square rooms via doors in the style of old Zelda games. You fight enemies, collect and buy power ups, and fight enemies with those power ups, which gives the game a good amount of variety. While the immense amounts of interesting items to collect make each play through interesting, the combat does not change much at all. The gameplay is single-minded, with uninteresting enemies and tedious boss-fights that amount to wars of attrition. Ultimately, this gameplay formula is not great, but may still be worth playing, if it were not for everything else.
The first part of "everything else" is the visual. I like to consider myself one who is not easily squeamish, and pretty much open in terms of my standards, but The Binding of Isaac tends to abuse that openness by constantly testing it. The opening cut-scene hints at playful dark humor early on: Little Isaac is just playing with his toys, while his mother listens to voices in her head in between bouts of watching televangelists, religious programming, and presumably a lot of Pat Robertson. One day, her religious mental episodes propel her to make Isaacs life miserable, and she goes to "cleanse' him with a knife, but not before Isaac escapes to the basement. In the game, Isaac is naked, fights enemies by shooting tears. Upgrades allowing increased firepower (shooting tears/crying faster) can amount to Isaac finding a wire hanger to impale his head with, a third eye for triple-misery and crying, his mother's tampon… and I think I'll stop with that item, you get the point. You can find coins by shooting piles of s*. That too.
Unfortunately, this turns the dark-humor into just humorless dark storytelling. Since you cannot save, and must attempt to beat the game from beginning to end, not being able to take a break makes it grating. Also, if you lose half-way into the game you'll have to repeat the same levels over again. While randomly generated dungeons, with random enemy spawns, and random item spawns may serve to ease some repetition, I often found myself getting a bit unlucky with finding new weapons, felt that the random enemies really didn't change much about combat, random dungeon layout means absolutely nothing since the squares themselves lack variety, and the boss fights, which take up a large amount of time just laying on damage, do not randomly change and so that repetition becomes unavoidable.
I enjoyed The Binding of Isaac as a short taste of the dark humor, some variety, and new ideas. But before long, before you've spent enough time to make the trip worth it, the problems rear their head and you become too queasy to continue.
Overall Score: 5.5