This was a fairly formulaic film but one I found rather enjoyable. True the highly trained agent seeks revenge. True he is underestimated by those hunting him. True he finishes them off one by one while cunningly eluding capture and managing to fashion highly dangerous (and fairly cool) IEDs along the way. Not to mention sneaking up on a guy that is supposed to be better than he is. The key here is that they made it interesting. He didn't go after revenge after his buddy was killed in combat (it was alluded to but not shown) he did it when his current way of life was disrupted (people setting you up for murder and trying to kill you will do that.).
All in all I thought it was entertaining enough and the acting was good although I have to admit the speech impediment of Glovers was more annoying the longer it went on...I hope it isn't real. The writing was witty in places but inventively so and the action, though expected in places, was fun to watch. It would give the Bourne movies a run for their money.