I've also been playing it. Like Balton, haven't finished. But my thoughts.
1. Beginning of the game drags through tutorial stuff, which I hate seeing in every shooter nowadays. I actually disabled the screen prompts and it kept getting me killed at one point where a metal dog is eating through a wrecked bomber because I didn't know I could perform a run-duck slide in the game. I felt silly after I turned tutorials back on and saw the big message "do this not to die lol." Yeah, I stood in that spot for 6 deaths literally asking the game what do you want from me. Immersion crept back in when I finally get into the Nazi compound and confront the game's antagonist for the first time, and it's a good thing too because that whole sequence was just kinda horrific and presented really well, really where I got into the game. Just hate it when games do this, this is what almost made me stop playing Far Cry 3 also.
2. Gun play is good and that's all that freaking matters in the end. Location progression is fairly linear but most of the areas are open ended in the sense of how you get to proceed. There was one encampment I entered and cleared using just my knife, felt pretty cool about it, and entered the next section only to get immediately spotted by an officer (they radio in MGS style and set off alarm). You'll have moments like this, extreme stealth ninja master and gung ho Rambo, all of it viable and fun unlike some trash like Deus Ex: Human Revolution. Getting jumped by dogs (they wear armor, for reals) puts the game into like a first person quick time event kinda thing that's not really a quicktime event (you have to stab them in the face enough times before they rip your throat out). Robots will turn you to swiss cheese if you try to carelessly pick at their armor spots (which you can shoot off and strap to your own armor supply), or you can try to focus on their weak spots with careful single shots. You can dual wield, change firing modes on some guns, toss grenades, and perform close quarter melee kills. Standard fare, some might say, but it all isn't very complicated and lends to the classic vibe of Id tech gameplay. At the end of the day, the game does this part right and that's all that matters, unlike Rage which forced you to do a whole lot of else.
3. Story develops in between gameplay chapters, usually before or at the end, and is good for the most part without going too far beyond the scope of its shudder pulp roots. The German characters, good and bad, are all pretty interesting. This is important because BJ is the standard, grim voiced, white action hero grizzled by war typecast protagonist. A lot of his hard-edged commentaries get lost in the fabric of the ensuing chaos on screen and I think I only heard a quarter of what he says. There's a couple of funny interactive moments, however, where BJ can do things like sit in a car or take a nap and have a nightmare. One part of note is when the the player clears out an office filled with Nazis, and the phone rings. BJ can answer the phone if he wants to and what the person on the other line says had me cracking up pretty hard. The game is loaded with excerpts of readable text via newspaper articles pinned to walls. There's one section of the game where you are stuffed in a safehouse manned by resistance members, and there are literally dozens upon dozens of these messages posted all about the walls. I gotta be honest, I read maybe two or three of these. They all seemed to fill the gaps of time between the prologue and the present day, mostly referring to unrelated story tidbits and things unrelated to the plot...things that might have bloated the game's running time if I cared to read the all, and I certainly had no incentive to. I like that they are optional but I felt kinda like a jerk because I didn't care about them. This reminds me of when I wrote all the ingame messages in The Ball and people who played it told me with honesty, "yeah I liked playing it but I didn't care to find any of those totems with the messages you wrote, sorry." I get it, I totally do. But they are there either way.
Yeah, I'd say check it out at least. It's got rough edges but there's fun in here.