Nowhere near ready even for an EA title. The AI of the zombies is awfil and there's no challenge in killing them.
Blueprint system for upgrades is as basic as it gets too. Find a piece of paper in an old beat up shack hidden randomly somewhere on the map. Voila! You got the expertise. So linear it's almost painful.
I usually look at reviews on Steam and think they are more often than not unnecessarily harsh for most games but in this case the opposite is true.
What other people are looking at when they give it a thumbs up is anyone's guess.
This could end up being a perfectly enjoyable game eventually but as it stands it starts off looking not bad at all, but as time passes and you discover how little point there is to the game in general, the sinking feeling that you've just sunk 20 hours into a game that's got no goal or rewards starts to dawn. Don't be surprised if your brain decides to file it under the 'do not open until 2024' category. It might just have a reason to exist by then.