DISCLAIMER: I did not finish this demo
Decent core gameplay (i.e., the "shoot, explore & loot" parts), but WAY too easy most of the time (on normal difficulty), with unexpected difficulty spikes a little way in. (I played with mouse & keyboard, and part of the problem was that I kept losing track of the mouse cursor/aiming reticle when things got hectic; maybe these parts are easier with gamepad?) Unfortunately, the loot itself isn't particularly engaging, given that I was mostly finding crafting materials (yawn) and the same handful of specific armor pieces and weapons over and over again; it seems like what generates is probably severely restricted based on how far into the game you are. The shooting is a little weird, given that it's essentially a side-scroller with depth--you can move further back away from or closer toward the screen, and you'll have to in order to fully explore and pick up certain bits of pre-placed loot. But it seems like you also have to be somewhat lined up with the enemies you're trying to shoot (in terms of how far forward or back you are relative to them) if you want to have a decent chance to hit them, which is awkward. (And, on a side note, in areas with pre-placed zombies--sorry, "hordelings"--it seemingly won't even let you hit them at all until they "activate" and start coming after you, which is stupid.) It's also a little awkward navigating around levels for exploration purposes--i.e., moving behind things, relative to the "camera". Basically, there's a reason why most games don't use THIS kind of two-dimensional world.
Gameplay-wise, the most fun I had was playing the utterly optional collectible card game--which I almost skipped. Mind you, it's not amazing, but it was a bit better than the action-crafting "RPG" to which it was attached. This is one of those cases where I wonder if both games might've been improved if they had been handled one at a time and released separately, rather than spending less time and resources on each part because they were developed at once so that one game could be crammed into the other.
The story and characters are...fine (at best), for the most part. The writing isn't great: in particular, there's one borderline-insane arsonist character who latches onto the starting character early on (it's a party-based game, and you can switch between anyone in your active party as long as they're not too injured), and--despite her immediately disliking the guy's general personality and being horrified at his disclosure of something he had done a bit before they met--she sticks with him, and after a couple missions, she's treating him like he's her zany-but-lovable old buddy, despite nothing having happened in between which either showed or excused her having been won over. Even in a game with a comedic tone, this is bizarre. But the rest (that I saw) was fine--not amazing, not terrible.
Visually, the game is also fine. The weakest element was the comic-book-style panels that tell parts of the story in cutscenes (some of them were just not very well drawn), but other wise, the game looks decent enough.
The only part of the audio side that I can even recall now is the fact that they used Banjo-Kazooie-style non-verbal vocal sounds in lieu of probably-too-expensive voice-overs. It worked well enough here, and wasn't really annoying.
Performance-wise, I don't recall having any major problems (frame-rate drops, lag, crashes, etc.) the couple times I ran the demo. It definitely gave my laptop (which meets the recommended specs) a bit of a workout on high graphical setting; I wound up turning it down to medium after the first play session, just so it wouldn't get quite so hot.
Unfortunately, there are games that do every single gameplay and story element better than this one did (even just within the zompocalypse/post-apoc settings/themes). They tried one or two things differently here, and I respect the devs for that. But I bailed out of the game after dying a couple times in the gauntlet and realizing I wasn't having much fun, so didn't care about "gitting good", and didn't care about the story or characters up to that point enough to even turn the difficulty down to maybe finish the demo.
I don't see myself ever buying the full game, and probably won't ever revisit the demo, either. But maybe I'd consider checking out a more developed standalone version of the card game, or something similar--as long as it wasn't some online-multiplayer-focused thing like Gwent.