Not great.
While I am okay with the 1st-person shooter style of the game, the on-rails element was extremely frustrating. I hated having no control of the character movement and often their head was turned in the direction opposite of where I was trying to look, preparing for oncoming enemies. I did find the controls clunky and the aiming awkward and difficult,the lack of ability to explore or even turn my own character very off-putting.
When you die and have to repeat an area, you have no control over how fast you move through that area and are forced to redo the entire thing, rather than trying to simply run through halls or avoid slower zombies to conserve ammo; this makes the game get eye-rollingly repetitive - fast.
This game had a lot of potential and could have been very awesome left with the ability to explore a little bit more on our own. Ultimately, though, the on rails facet of this game all but ruined everything that could have been very cool.