I think they meant more on a base level that the core mechanics are all basic standards of the top-down adventure game genre, and that they haven't ventured any further than that, (which I personally don't see as a bad thing as long as those core mechanics feel good to use, and they do). I guess they were looking for more of a unique hook in the first few seconds of gameplay, and I can understand that. Maybe they would've enjoyed the style of the Bump RPG prototype PXS worked on before?
It's hard to really make a true judgement one way or the other at this point if you're discovering the project with a fresh pair of eyes. When you're playing/watching a build that only really exhibits some of the basic niches of the game, (i.e. the physics system) you'll either accept it because you love the genre and just like good execution of the genre, or be hesitant to accept it because you're expecting more from that genre and maybe aren't as swayed by just seeing a more simplistic execution of the genre.
Problem with the physics being the main draw for DDrop's pre-alpha build is that those mechanics are really only heavily apparent when you play the game yourself rather than watching it, and even then some people find physics to be more of a tacked-on thing rather than a really deeply thought about mechanic.
Other problem is, as you both mentioned, we're not at the stage where further distinctions that would separate DDrop from other top-down games are present, so people definitely have reason to maybe be a little bit worried. It's really gonna go sort of half and half with most people I'd say. Some are just gonna enjoy it for what it is and some are gonna question if there's more than what they're seeing. Hopefully there'll be something solid to back up that it's a game worth checking out for those who are still skeptical down the line. The more people who end up checking the game out, the better chance we have to see it grow even further down the line with new classes and areas...
So yeah, I wouldn't pass it off to CoD players who won't be satisfied by anything non-Triple A title-worthy; these are legitimate concerns people have, it's just that it's too early to pass final judgement on the game off of if it's got a really apparent gimmick to it. Sometimes those subtle touches really make a good game into a great game, and I think DDrop is one of those cases.