×created a blockade in the lower left with one square open near the left orb. I left the top left giant alive to block up that hole. The hole is important, though, because most of the small golems are attracted to it, while only a few come around the south side of the blockade. Once you deal with the southern attack, the clean up is easy.

×I killed all four giants at the start.

×But I agree the idea with the rock giant closing one access to you seems a very good one. I didn't try it though.

×After lighting the first fuse (make sure it's north or south because that's a shorter distance; I'll give instructions assuming it's south), make your way to the opposite bomb; kill as many golems as you can on the way, but make sure you get there in time to avoid being killed by the incoming golems from the northwest. Then stand on the checkpoint 1S1E of the bomb (the obstacle will protect you there), and block yourself in on the south and west (including the southwest corner). All the golems will head around the still-closed area to the only way to get at you on the east, so when the bomb explodes and clears the blockage, all the golems will be east of you, making it fairly easy to kill them safely without getting blocked in.