Iron Man 2

This achievement is obtained in the final mission and only applies to the Iron Man sections of the level.

The achievement description is a little misleading as you CAN get hit, as long as your shields ( the outer blue line ) absorb the damage.

If one of the chunky light colored sectors goes that means you've been damaged, just pause and reload check point to try again.

To actually accomplish this just dodge around him with LB and shoot after he charges and misses you. I'm not sure if getting hit by the laser probes he launches matters but these are easily dodged using LB. Also note when on the 3 lasers 1 of them is always alot harder to kill until the other 2 have being defeated.

I did this on easy on my 1st play-through so its not that hard but if you want the easiest time, load Iron Man up with dual lasers and the ultimo enhancements which maxed out your damage.

As the achievement says this must be done on the last mission (M8): ULTIMO.
But you don't have to avoid damage for all of the mission. It's just the Iron Man sequences that count and there also only the part where you fight the DeWitt, the cannons do not count.

So for an easy achievement, set the difficulty to easy, tune up all your weapons and blast the mad man with any weapon you want, he will die in seconds. If you still have problems, just dodge his attacks with LB.

For this achievement you must finish the final battle against ULTIMO without taking any damage to your inner shield integrity. The outer shielding that recharges can be damaged and you will still get this achievement. This is alot easier than it sounds. Simply follow the steps I listed above for the final battle and if you get hit pause the game and select Restart Checkpoint to try again. The sections are very small so you won't be backtracking a bunch to get it. If you are having trouble with this wait until your Hard playthrough is done THEN change the difficulty to Easy in the HQ and replay this level for the achievement.