Tap Play on the home screen to Choose a mode. Each mode shows your best score.
Classic
Memorise objects round after round. No timer: take your time to find the new object. The game ends when you run out of lives.
Time Attack
Pick the new object before time runs out. Each round has a timer: 5 seconds at first, then shorter. Running out of time costs a life. Time Attack gives 1.5 times the XP.
Reverse
One object vanishes. Spot which one! First the screen says Memorize the objects! Then one object disappears and a row of candidates appears: Which one vanished? Reverse gives 1.5 times the XP.
Daily Challenge
Same puzzle for everyone, once a day. It gives twice the XP and keeps a day streak. See Daily challenge.

