Credit goes to derekwst3
for the tip. I've not seen it in this forum so I've decided to share that with you guys, may help anybody willing to get "Omega Level Mutant" and "Alpha Level Mutant" achievements easily.
Follow the X-treme achievement glitch posted here: http://www.xbox360achievements.org/f...d.php?t=337571
Then, when you select the last level on X-treme difficulty and the game starts, equip all Quicksilver X Genes. Let the enemies attack you and when you're about to die, activate your X Mode (LB button) and let yourself die. Note: It requires 4 bars of your X ability to activate the X Mode. You can replay the first challenge 2 or 3 times before you start the last level to max it out.
When you respawn, you'll notice that everything is like in slowmotion. It makes all the fights, even the last 2 bosses really easy!
Hope this helps