Considering the technical limitations 1) must be mostly 2D interactions, but not always 2) must have been able to run on a handheld and relatively easily upgraded to beefier platforms .... I have been extremely impressed in my first few hours with the game.
It's not as good as the other games (of course), but that's impossible with these limitations. However, the combat is fun if somewhat limited, there's lots of batclawing, exploding, detective moding, exploring and whatnot. There's not the open-world flying, but Arkham Asylum didn't really have that either. The odd thing is that this one has more of an explorative... mazelike... dungeon feel to it, which I thought was pretty cool/fun. It is closer to Arkham Asylum than the other, open-world game. Which I don't think is necessarily bad, just different.
I do see why people would not recommend it, since the other games are all better (because they didn't have to run on a handheld). However, if you've already played all the other ones (Asylum, City, and Origins), then this one should be next on your list to play IMO because it really is a good game. It's definitely a batman game :)
SIDE NOTE JUST IN CASE A DEV READS THIS: The main two things that would need changing (which I think would still let it run on a handheld) would be (A) fully rotatable map on all axis, and (B) minor tweaks to detective scan mode, (C) quicker restarts for boss fights.
(A) The map is set currently in an isometric locked view, which has limitations when showing the map from the perspective of the user, height of objects, and depth in complex situations (like a large sprawling map). I really like that the maps are huge and complex, and I don't really have that big of a problem reading the map (but probably because I use Computer Aided Drafting a lot), but I can see it being very difficult for many people to use.
(B) Currently, the detective mode only highlights main, mostly obvious items in the environment (switches, thugs, keypads, doors, stuff like that). To find explodables, blood, or some collectables, you have to hold down the detective button and it scans in a circle. There needs to be an upgrade somewhere in the game (and maybe there is) that enlargens the circle and speeds up the scanning speed by at least 2 times the speed. These are really my only two complaints about the game that would be fixable within the technical limitations. I think that's pretty good considering it ran on a handheld. Don't get me wrong, I do not want you to just change it to how the other games have it. I actually do not like having to be in detective mode so much, so that's why I like the scanning function, but it needs to be faster and more responsive is all (even if it's 33% into the game).
(C) For boss fights, when you have to try them multiple times, you are forced to not only skip the boss intro cinematic, but also watch the first part of the boss intro that is unskippable (which is not long). On normal fights with previously seen and predictable components, this is fine. However, all of the boss fights have a "figure it out" part to them (which I don't mind), but having to repeat much of the fight which I have already seen/dealt with does get frustrating since each of the bossfights have a "OH that's what I should do..." moment. At that point, the player just wants to dive back in quickly and try it again.
I'm only mentioning these things though, because I'm hopeful that there will be a sequel that incorporates these elements, because I would totally buy it for PC :) I was reluctant because of the bad PC reviews, but I was very glad I didn't skip this one.
Also I saw some videos of the handheld version, and you guys did a great job upgrading it to be closer to a PC gamer fidelity. I know some people complained about the graphics, but I thought they were fine for what you were working with (and I know they are just longing for the other Batman game's graphics).