Problem numero uno: AI. Your enemies don't appear to have any, or at least any that has advanced significantly since the days of Quake II. That's fine. We don't expect Zombies to act smart, and the game would probably be impossible if they did. What is a problem is that your squad-mates are equally clueless. I've seen them standing with their back to a hail of bullets while they contemplate their next move. I've groaned as they each take it in turns to walk into the target-zone of a camped goon with explosive projectiles seemingly because they wanted to join their mates who had already been downed at the same spot. From the beginning, you're assaulted by explosive zombie enemies, yet even hours on your troops haven't learnt that a downed exploder always explodes one or two seconds after collapsing. Nor do they seem capable of targeting the yellow weak spot pustules on the beasts. These guys are meant to be seasoned veterans? Why, then, are they so thick?
To soften this, Jericho throws in a Gears of War healing system whereby downed chums can be resurrected by getting close and hitting X. However, combine this with Jericho's tendency to throw an endless stream of enemies at you, and at times the game turns into a farcical heal-em-up, where you race around like a headless chicken trying to keep as many of Jericho squad fighting fit as humanly possible - just because this is the best and only way to avoid another trip to the reload screen.
And sometimes you'll fail, partly due to the sheer quantity and ridiculous bullet-resistance of even the most basic baddies, and partly due to the lemming-like tendencies of your squad. To make this really annoying, the checkpointing is often very poorly done, meaning you may face a repeated ten-minute trek through the same four battles every time your team goes down. Adding insult to injury, you have to go through a yes/no prompt every time you reload, and Jericho even throws in annoying in-game cinematics straight after some checkpoints, meaning you can enjoy the same weak lines of dialogue many times over.