Maybe I have to upgrade my claim of sucking at the Binding of Isaac to say that I'm not all that good at it. My highest wins streak, after all, is five.
On one of my runs to complete everything on hard mode with all characters I got an unexpected combination of items that was completely mind blowing. I know I had picked up Sacred Heart before because it was checked off on my item collection screen, but I didn't recall it. It turns out greatly increases your damage, reduces your tears and gives a homing effect. I also had polyphemus, which greatly increases your damage and reduces your tears as well. Most importantly, though, I had rubber cement, which makes your tears bounce off of enemies and walls. The bouncing seems to extend the range of the tears - I don't think it's a full reset when they bounce, but certainly with many bounces they can stay on the screen much longer than they normally would.
The powerful homing effect of sacred heart meant that sometimes after bouncing off an enemy the massive tears would turn around and hit that enemy again. The second time they would be moving slower and bounce less, and then they'd end up just resting against the enemy, killing it very quickly.
My tear rate was very slow, but I was clearing nearly all rooms with only a few shots. I cleared some rooms with a single shot - rooms that don't seem remotely possible to kill with a single shot. Killing a a boss with a lot of health with one shot is one thing, but killing three super sloths with one shot seemed just plain weird. The giant white ball of death homed over to one of them, killed it very quickly, bounced off, headed to the next one, bounced off, and headed about halfway across the room to kill the third. I killed two fallen with one shot. The shot simply hung around the first fallen until it split, bounced back and forth to kill both the small fallen, then headed over to the other fallen and killed both of them as well. The Lamb, with it's massive health pool, managed to take three tears to defeat.
It's pretty neat that even as I was rounding things out I still found a new brutal combination of items, even if it involved Angel Room items that you'll almost never get. I think that the expansion is due in the next couple of months, and I'm sure I'll be playing the hell out of that - and being not all that good at it by some absurd standard.