I kind of agree with Swiftcoder. Skin them any way you like, give them any name you like, but what you've described will still feel like zombies to people. L4D and Resident Evil may call their creatures zombies, but their basically just human mutations with a nasty rage problem. In L4D they actually are the walking dead, but in some of the RE games the zombies aren't corpses at all (Majini from RE5). Even Dead Space felt like a bit of a zombie shoot 'em up to a certain extent.
My real question is; are people really sick of zombie games? I think maybe they're sick of bad zombie games (since there are so many), but I don't think the genre is losing fans.
If you really want to avoid the zombie genre consider removing some of the basic requirements for your creatures.
"Driven by base instincts"--This can easily apply to most zombie critters, but also to numerous other things. How bout a behavioral pattern of some sort? Maybe a learning curve as the game progresses (Think Jurassic Park--the raptors learn to open doors, OMG WE'RE SCREWED!!!). I know this learning curve happens in some zombie games, but usually in a drastic way (zombies go from claws to rocket launchers in one level). It's always a bit unnerving when you're playing a horror game, you see the bad thing, it sees you, you ready to shoot it down as it inevitably charges right at you like all the rest... and suddenly it runs away. Consider a zombie ambush that actually feels like it was set up by the zombies and not the game designers (I Am Legend vs L4D Zombie Rushes)
Practically Blind--Is a pretty standard zombie feature, that's why the swarm is always following the protagonist. I'm a fan of this trope, but it's another thing you may want to discard if you want to avoid the zombie genre. It does make for some awesome storyline (High School of the Dead does some amazing things with blind zombies).
Drawn to Life--Definitely drop if you want to avoid the zombie genre... why not give your nasties a modicum of intelligence and give them a reason for wanting to kill anyone unlike them. "Mutant good! Normie bad!" Is the simplest level, but also consider what it would be like if your creatures were of a hive mind of some sort.
Nocturnal--Again... very typical zombie trope. They always move in larger groups at night.
Can only be killed by 'Removing the Head or Destroying the Brain'--I quoted Sean of the Dead if you didn't notice... probably enough said on this factor.
Infectious--It's very rare to find a zombie game that doesn't feature this.
Either just go with what you've got (it looks great and sounds interesting so far), or you'll really need to make some drastic changes to your game to avoid it being a zombie type game, which in my opinion is totally fine. I'm not sure where you heard that zombies were losing popularity. Walking Dead, Resident Evil, Day Z and many other zombie things are still insanely popular.
Or are you more worried that you're game will simply get lost in the ocean?
I never said she wouldn't beat the absolute crap out of him; just that she's willing to show him the same mercy that he showed her. Yes he was the tool that brutally murdered her father, but it wouldn't be the first time that someone was more concerned with the man that gave the order. If it hadn't been Enkidu it would have been someone else, and they may not have relented.
I see your point about Ai's comment; I was just trying to give her some arrogant things to say (as is befitting of the character I'm trying to portray), and not a quote which made her seem to claim that women were better than men--her only belief is that she's the greatest, better than anyone. Obviously Kung Fu can be used for many things; Ai wants to use it to kick the crap out of people and show her superiority, but with Aito I'm trying to lean on the movie stereotype of the wise martial artist who practices as a way of life and would rather sip tea than fight. With Mali Mali there is some doubt about her father--she knows about the gang wars. When they ended her father took her and they abandoned their home and went into hiding, so she suspects he may have been a criminal of some sort (if the story were to get complex enough Enkidu would refuse to tell her who her father was, then Gilgamesh would show up and announce that he was one of the fallen crime lords or something like that... maybe he's one of the guys who hired David).
I'm a little confused by your subject heading. A Dystopian story is typically about a society in which something is horribly off. Think 1984, Fahrenheit 451, A Clockwork Orange, or Brave New World (The Time Machine is a mixture of the both Dystopian and Apocalyptic genres). I think the allure to these novels is driven by our own paranoia or pessimism. Our fear that if things are left unchanged our society could slide into becoming one of these worlds.
As far as post-apocalyptic I think the interest is a lot more complicated. As an artist it allows you to experiment, to tell your own legend about how the world will end. You can do almost anything and paint almost any picture. You can take real world buildings/cities and smash them however you like, or leave them standing hollow and haunted. It also allows a less restricted world. You want deserts to Road Warrior it up? Drop a few Nukes, have the Borg scoop up your cities, set the date several thousand years after most of the world has eroded away. It also allows the author the power of political commentary: what real world issues do you see as a likely cause for the end of the world? Resident Evil seems to think a corporation gone wild mixed with militaristic agendas will be part of the cause (even though I wouldn't classify RE as apocalyptic).
As an audience I think that we are frequently pondering the future, and for many people that includes wondering how and when the world will end. Sometimes our paranoia is piqued at an ominous news story (google Earth Moaning), and we look to literature and art to answer our curiosity on the subject. I'm sure the pool of people who think zombies will bring the end is small, but it's my opinion that the Zombie Meme is an entirely different beast than the Apocalyptic one; even if they operate within the same genre.