When sliding down what looks like a series of rocks, Shrek gets hit in the groin.
At least twice in the film, Donkey falls from a high height.
Donkey mentions ogres grinding bones to make bread. Shrek replies "How about I decapitate an entire village, stick their heads on a pike, cut open their spleen and drink their fluids. Does that sound very nice to you?" This may be considered too much for an average family movie.
A gingerbread man spits on an antagonist.
There is a wrestling scene.
Donkey tips over a big barrel to squash some warriors. Shrek takes some more out with a series of pro wrestling moves.
Robin Hood and his men show up and he briefly holds a knife on Shrek. Fiona, however, goes into martial arts mode and takes out all of the men (with punches and kicks, etc.) with one of them shooting an arrow at her and Shrek. We then see that the arrow struck Shrek in the behind (no blood or gore, although she has to pull it out and we then see what looks like a tiny bit of blood on just the arrow).
A dragon lands where the guards are guarding. The guards run away and the dragon follows them. Nothing happens.
In Fiona's castle their are many skeletons, armor of dead warriors, and various bones of men killed by Dragon.
Shrek and Fiona blow up a frog and a snake like balloons and let go of them floating up towards the sky. They both most likely died a slow and painful death.
Fiona singing causes a bird to explode. When the singing stops, we see the legs of the bird still on the tree branch with little smoke coming out of it. Nothing graphic or detailed but played for laughs.