Halo Wars is a real-time strategy game that uses species and vehicles seen in previous Halo games as well as new units.[2][3] The controls use the A-button primarily for selecting via 3 methods; tap to select one unit, double tap a particular unit to select all units of that class on screen or "paint brush" which selects all units that the "brush" is dragged over.[4] Selecting a unit gives the player the option of commands and selecting certain buildings brings up a "circle menu", said to be the most important menu in the game,[4] taking up the whole screen which is used for creating units and buildings.[4] The game's lead developer, Graeme Devine, has said that the emphasis is more on combat than economy; it is necessary for the player to "manage a battle instead of watching it",[1] and while resources are still present they also have alternative forms such as time and the number of units present.[3][5] Some campaign missions will take the focus off resources but skirmish and multiplayer matches still require some management of an economy.