 Planet Moon designed the structure of the single @-@ player mode to be a gradual learning process for the players ; the game would introduce new command sets to the players as they progress , and encourage them to repeat using the new commands for that mission . From the start of the project , the team intended the controls to be simple , and mapped commonly used commands to a few keys . Focus groups consisting more than 25 testers went through this design to verify its ease . Planet Moon aimed for a complex artificial intelligence ( AI ) ; computer @-@ controlled characters would evade shots and take cover . The enemy AI would plot its actions according to long @-@ term goals . The development team consulted Mark Frohnmayer , lead programmer of the multiplayer game Tribes 2 , for advice on implementing the multiplayer portion . To balance the characters in combat , Planet Moon focused on characteristics that could affect the fighting capabilities , instead of tweaking the damage output . The team faced a tight schedule , and abandoned several features initially in the game . Early designs allowed players to change the landscape ; they could gorge out water channels and isolate segments of the land by playing as Reapers . The Kabuto character initially could bake mud into " mud shepherd " units and use them to defend its herd of food . 
