Anti-air: A lot of things in Injustice can be related to properies in sf4. Movement, jumping, backdash, comboing off duck jabs, focus attacks, throws, ect. One thing that is not like sf4 is anti-air. Since there are no dragon punches or ex flash kicks or ex spinning bird kick or whatever, you have to rely on other means in Injustice. This will entirely depend on each character with their normals. It also depends on spacing. Lex's u+3 is pretty decent anti-air, but only when your opponent jumps directly on top of him just above his head. Batman's b+2 is also decent anti-air, but again it won't work too well at certain angles. Wonder Woman's d2 is one of the more reliable of the three demo characters, but is slow so you have to be concentrating and looking for a jump which opens you up for people dashing in. And can lose to some of the better jump attacks like Lex's jumping 3 at the right angle.
You can also use a mb (meter burn) b3 or f3 as anti-air as well much like sf4 focus attack. Since b3's and f3's are pretty slow, unless you do them very early and hit them during their landing frames, your opponent typically is able to block in time if they see you charge it up. (Again, very sf4ish) Plus, sometimes you don't have meter to spend.
The most reliable anti-air in the game is pre-emtpive air to air attack. Unlike sf4, you can juggle your opponent after an air to air exchange. If you know for sure someone is going to jump, jump with them hit them air to air with a jumping 1 or jump 2 and you can follow-up with a full combo. In MK9 a air to air jump punch caused massive scaling, but this is not the case in this game. For example: Batman can do air to air jump 2, (land) b2 xx db+1 mb, b3, j3, b2,3 for roughly 40%.
While pre-emptive air to air is the most reward for anti-airing your opponent, its also the riskiest. If you throw out a jump attack and they did not jump, you will land in front of them giving them free damage.
dat'll come with game time
