Cannon1's attack.
Cannon2's attack.
Cannon3's attack.
Cannon4's attack.
Update 26/06/2021: polished expert; added easy, normal, and hard
Update 27/06/2021: fixed a bad movement on normal
Update 16/06/2022: unlisted
Update 20/08/2022: overhauled XD, brought up to date, relisted