Metal Slug Mobile 3 is a Run-n-gun game made by SNK Playmore for various cellphone models. It is a enhanced American port of Metal Slug: Allen's Battle Chronicles.
A new enemy has appeared on the horizon in the shape of a relentless zombie army. Just as Sgt. Allen O'Neil of the Rebellion Armed Forces is about to engage them in battle, he realizes that they are in fact his own soldiers. With no way to communicate with the zombies, no time to find another solution, and no way to call for backup, it appears that Allen has little choice but to fight his once loyal troops. Luckily for Allen, being a notorious bad guy means he has a huge cache of devastating weapons at his disposal...
By the first time in Metal Slug, you are able to control one of the bad guys. And it is not just any badguy, it's Allen O'Neil himself! The game plays like the previous cellphone game, but now you face some bosses and rescue the regular rebels, while fighting blue zombie clones of them.
The bosses are: