In the end, Riddick fares better than most movie tie-ins, mainly because of Gaming Corps' dedication to good stealth play and stage design. It could've been better, though, especially with superior action elements and more involvement from Diesel.
I guess if shallow stealth games are OK with you, you'll find this one to be a worthy entry to the app store. This is definitely not the iOS version of Riddick that rivals any of the franchises previous efforts, fair warning. In my opinion: your options for a more entertaining stealth game, on the App Store, are numerous.
Where Escape From Butcher Bay and Assault On Dark Athena showed how games can complement and expand a film franchise in unique and interesting ways, The Merc Files feels like a rushed, irrelevant addition to David Twohy’s B-movie universe; one that would have been best left on the cutting room floor.