Its a allright action game with great moments and really bad moments.
Avatar is a this person action game where you play either as human or Navi. Both sides have a different play style and this is a nice twist. As human you play a soldier who is send out to deal with navi and destroy their forrest and homes. Thats it basicly..you don't really do much else than travel to your quest location and shoot at everything in the area...now and than you need to activate a device but thats about it really. And most of the time you need to travel a long distance. Luckely they let you controle some vehicles like a buggy, a boat, a helicopter or a mech. Some vehicles can attack others are just a transportation vehicle.
The vehicles controlles are pretty doable with a keyboard. Though flying up and down with a aircraft can be anoying. How ever its still doable and while airborn you don't really have to be that agile so you will probally surive your flight time anyway.
As humans you depend on guns, guns, guns....you just keep your finger on the trigger and shoot everything that moves..Because even the plants in the jungle will attack you. This makes the jungle not only beautiful...but also verry dangerouse. You have different kind of weapons like flametrowers, grenade launchers things like that. Different enemies are weaker against certain type of guns than others.
The humans are pretty easy to play, as long as you keep your ammo filled you are hard to kill with your healing skill that regenerates pretty quickly. Also there are enough ammo points where your ammo is refilled. And once done with your mission there is most of the time a teleport device nearby to bring you back to your mission giver.
Where the humans are easy to play i found the Navi much harder. This because you depend on melee combat. And even though enemies are dying quicker from a sword than a gun you still need to get close to your target...and with the easy health drop this can be frustrating and really hard, especially in the begining you will find yourself retreating allot to first get some health again than to charge at the group again and repeat this over and over again cause you are to weak to fight groups.
But it must be said that the melee kills give a bigger satifaction than shooting a grenade at the enemie when playing the humans.
The navi also suffer from boring repeatable quests where you either have to pick up flowers or defend a spot, stuff like that.
I haven't played the navi much so i can't tell if they improve more later on. What i can say is that flying is a pain on the keyboard, you really need a controller otherwise even landing is a hell. Since i don't have a controller the fly missions where unneedingly hard...i flew into mountains and the ground all the time and the camera didn't worked well with me either. This is a real shame cause i found the navi more mood setting than a standart human scifi marine. Also a benefit from being Navi is that many plants that want to kill you as human leave you allone when being Navi.
Avatar has also a online mode, but this i havent played, but my guess is that the humans are overpowerd with the guns...sure Navi will be stronger but they need to get in range and thats hard if you aren't strong against bullets.
Also there is another game to play in Avatar. Based on risk..but no one will bother with this mode. Its not fun to play and you get enough armor and weapons by completing the missions so you can forget about this unfriendly to players kinda mini game.
There is allot of action as said and that tends to make the game boring, cause all you do is shoot your way trough the game. And do the same type of missions all the time and suddenly the game is over. However if you don't mind allot of action and want to enjoy a really beautiful world than this is your game.