That game is literally Left 4 Dead. Like, it's not even a new game. It's just a bad mod. The menus, the 4 characters, the downed status and helping teammates back up, the bot AI, the floating tooltips, all of it... It is blatantly obvious that it's Left 4 Dead with a new coat of paint. A bad coat of paint. Someone fingerpainting while blindfolded and drunk. The enemies are obviously using the L4D zombie AI, except they only tend to come one or two at a time, which makes them stupidly easy to deal with since they're designed to be a challenge in hordes of 10-20. And it's like that with everything else they've changed. They swapped the first aid kits for tiny health pickups, but kept in the fact that you have to use them to pick them up, which is annoying if you have to do it every 5 seconds. They appear to have failed to copy the special infected (or at least the video didn't get that far) so you are just fighting generic enemies that run at you and die.
The game just has nothing to recommend it. Any fun you would get out of the gameplay would be vastly improved by just playing L4D. Unless you really get off on shooting Mayans (in which case, you should consider therapy) there is literally no reason to play it. I'm totally with TB on this one, I have no clue how Valve allows tripe like this on Steam and yet has famously denied some fantastic games that deserved to be on there long ago.