I deleted Shadow Guardian because of the climbing and seemed to be tedious. Downloading Unearthed as I type this. Looks decent.
Max Payne is definitively worth putting time into. It might be a little dated, but it's still a lot of fun to play. And this is coming from one who only has the PS2 port, the WORST version if the game. I still had a lot of fun with it and beat the game. I've heard the iOS version's controls are so good now, that it almost makes the game too easy.
Decided to go with Zombie Infection and Shadow Guardian (again). Zombie Infection has quite a few sound bugs and glitches.
I have it. Played up to level 6. I do like the game but it has become somewhat tedious. I would love to see Gameloft do another Splinter Cell or another Silent Ops type of TPS.