Chapter 2, Checkpoint #5 (What I Do Isn't Very Nice)
Mutagen- Vitality 2
If my description doesn't help you then watch the video on how to get the Wow! achievement. After killing the two W.E.N.D.I.G.Os', Grenadiers', and Goliaths'. You will go past two military vehicles and into the forest area. Turn your Feral Senses on. There will be a fallen tree for you to walk up to get to the first ledge. The ledge after this one you will have to jump to get to. Once on top of this second ledge go forward a few steps and you will see two fallen trees. One in front of you on the ground that will making walking hard for a split second and one just past it to your right. Go to the one on your right and walk up it to the secret area where the sword and skeleton are. It will be in the corner to the left.
Mutagen- Experienced 2
You will get in a room where you have to hide from the sniper. As you are running between cover and the generators you will see his laser sights on you. Go all the way towards him, ignoring the stairs to your left and going behind the last generator housing. It will be in the corner to your left.
Wolverine Action Figure- X-Force Suit 1/2
Climb the stairs that you saw to your left before getting the Experienced 2 mutagen. Now go left at the top of the stairs away from the sniper to get the action figure that is all the way down here.
Chapter 3: Days of Future Beginnings
Chapter 3, Checkpoint #2 (Project Wideawake)
Mutagen- Inner Rage 2
Inner Rage 2.jpg
At the very beginning of this check point you will be forced to go into a vent. Once you drop down from it turn around and you will see the mutagen.
Chapter 3, Checkpoint #3 (Betrayal)
Mutagen- Samurai 2
When you finish your oh-so long journey down the elevator you will be in a place you should recognize from Africa. It will be the same place where you used pressure plates. To get down to this area once again you have to cut a rope. To the right of the rope where the wall behind you and beside you make a corner there will be a ledge. You can either double jump here or you can cut the rope, double jump back up to where you started and climb the rope up. You will see the mutagen easily by climbing the rope you cut, it will be on a wooden ledge.
Mutagen- Unstoppable 2
Soon you will come to a larger room, if you have your Feral Senses activated then you will see three large statues. One you will have to jump to it's feet and unblock it's path like you have done earlier in the game. Before jumping to the lower area look to you right, where the three statues are facing. There will be stairs that you will have to use after freeing the statue. The mutagen is under the stairs in plain sight.