 In addition to the single @-@ player campaign , limited multiplayer functions are available through the Nintendo DS ' Wi @-@ Fi functionality . When the connection is active , players can battle each other in dedicated maps . Units can also be loaned between players , and an online shop is available to purchase new items and weapons with in @-@ game currency . The game also has a time @-@ based function where , when the game is left idle while characters are in the " unit barracks " , a meter will fill up and the characters will perform limited autonomous actions : these actions can involve leveling up , or crafting new items and weapons . The game can be played with two modes : Classic Mode , which enables permanent death for characters defeated in battle , and the new Casual Mode , which revives fallen units for the next battle . In addition to this are four difficulty levels : " normal " , " hard " , " maniac " and " lunatic " . 
