After a few more hours spent with the game, I've gotten used to the kinda awkward mechanics, though I still have a few bones to pick with it. 

The interactibles are incredibly over-powered and they shouldn't be unblockable. While they are nowhere near as unbalanced as the random items in Super Smash Bros., it's hard to take Injustice as a serious tournament fighter (which I assume it's trying to be) when you can take off nearly a quarter of your opponent's life bar with the press of a button. Granted, none of them are unavoidable, but it's pretty damn hard to avoid some, if at all in certain situations.

Then, of course, you have some character traits that are clearly better than others since they're applicable to more situations. Grundy's for example allows you to multiply your power or defence by 2 (or whatever the actual value is) if you complete his chain of throws, and the effect lasts for the duration of the whole match, or until you decide to use a different effect. You can then use this to your advanatage and create set-ups that do over 70% damage or you can significantly reduce damage done to you. 

Compare the previous trait to say, Ares', which basically acts a projectile and/or combo extender that has cool down time and doesn't really offer *that* much more of a edge over your opponent.

While the idea of specific character traits is interesting, they seem more like gimmicks than ideas that serve the core game play (The Flash can even initiate bullet time - and that's something I just find ridiculous).

Also, while I'm not all that into memorizing frame data for fighting games, it's a nightmare for those that do because after some research and watching a good number of tutorial videos, turns out the frame data displayed on the command lists are wrong. Not much of a complaint from me personally, but I understand why this would be problematic for the much more dedicated players. 

But with these few complaints (and a few more that I'm too lazy to write), is the game good fun? Well yeah, it is, once you get comfortable with the controls. But it is definitely in need of some patches.