Double click the flag to start, then you can use a jump or an item, jumping allows you to select a slime to attack then press [Space] when landing to deal more damage. Under items you have three apples which heal 10 HP each and and bolt which deals 10 damage to all slimes. After choosing an option it's the slimes turn, press [Space] when the slime hits you to reduce damage. The battle ends when all the slimes or Scratch Cat get defeated. Each slime has different stats: Red 18HP 8POW 0DEF Yellow 22HP 4POW -2DEF Blue 20HP 2POW 2DEF.