Cheat codes work with this game and so do creating your own scenarios.Quick overview
-Use the Editor to:
-Place a ton of Gaia Gazelle
-Place some Player 1 Nuke Troopers.
-Make sure you load the scenario up in Single Player - Custom games
-DON'T use the steroids cheat. Recommended quick method
For this particular achievement I recommend just building a scenario since you only need to kill them quick with soldiers. No need to actually hunt
Setup your scenario to have a ton of Gazelle's
for Player Gaia
. If you also need the other achievement for the Lion then add a Lion (Alpha), Medusa and 20 heroes and 200 temples (or a 100 and just restart the scenario when done etc).
Then switch to Player 1 and add nuke troopers
Now save your scenario and load it up through Single Player - Custom games
and select your scenario in the top right of the Lobby options
Just kill all the animals with your nuke troopers, no need to harvest them.
I hope this helps. Non cheatish clean method:
I recommend playing on the map Oasis because it has plenty of hunt. Watch out for the lions though! You can easily get about 25 gazelle's and 5 elephants on most Oasis maps even in 1v1