The Germans learned a lot about tanks from the Russians, who used sloping armor on the T-34s. Up until then, nearly all the German tanks had nearly vertical front and side plates. Another big disadvantage German tanks had was narrow tracks which would allow the vehicle to sink into the mud, especially in the rainy season or after spring thaws in Russia.
The Tigers also had a weak point in that they didn't have much ground clearance so they would hang up more easily than many other tanks.
Favorite Tiger tank quotes:
"Tigers have one weak spot: it's ass. You have to hit it point blank and you have to hit it from behind".
"To a New Yorker like you, a hero is some type of weird sandwich, not some nut who takes on three Tigers."