撃
strike · hit · attack · beat
撃 is striking — a single decisive impact, with timing. You see it in attack (攻撃), in shock (衝撃), in counter-blow (反撃). The mini-game above maps that meaning onto a rhythm-tap drum: a ring closes in toward the centre, tap when the ring meets the drum. Eight clean strikes on the beat and the kanji is yours.
Common compounds: 攻撃 (kōgeki, attack), 衝撃 (shōgeki, shock, impact), 打撃 (dageki, blow), 反撃 (hangeki, counter-attack).