There are several checkpoints throughout the level. I found that rolling around a lot was my saving grace on this whole level. Make the minotaurs miss and roll behind them and get a blow or two in before rolling again. Stay on the move! I had the execution reward set on Health on all but one checkpoint.
On the checkpoint "Rescue the Romans from Being Burned Alive" you start out in the swamp. There is a dead soldier with a pilon in him to the left and then again to the left there is another 2. I tried to use them and ended up being 50/50 on the helpful scale. What I ended up doing to get past this part was to go over by the hut that that minotaur with the torch will try to set on fire. I set my execution reward to focus for this part only. I would pretty much continuously roll around taking shots at the minotaurs that would come after me being especially careful to avoid the Big Minotaur with the stone hammer. When the torch bearer gets to the door of the cage he will have a red skull over his head. Just go over and execute him and gather the execution points. The torch bearers just keep coming so just try and take out as many of the little minotaurs as possible while waiting for the next one. Continue killing the torch bearers until the focus is enough that you can slow time and take out the Big Minotaur. Once he is defeated, mop up any little ones you may have left and then you can move on to the next checkpoint. I don't know how many times I played this level until I finally came up with this solution so thought I would share with anyone else out there trying to get this achivement.
The next two checkpoints are fighting Gott. My same strategy was employed. Roll around A LOT. Basically, roll towards him when he swings turn around and roll towards him again so that you end up behind him. He does a swing, turn swing, stand there. So you do a roll, turn, roll, swing swing. I usually got 2 sword swings in, sometimes only one, occassionally three before he started moving again. Watch his health meter. When it gets to about 1/2 gone there will be color prompts! If you don't hit the button at the right time you will get hit and it takes a ton of health. Be ready! Once you flip him over your head you can get one or two good whacks on him. This happens a couple of times so stay on your toes.
Hope this helps anyone out there still looking for some tips on getting this achievement. Good luck and take it one checkpoint at a time!