gunroar 0.15.dfsg1-9build4 (s390x binary) in ubuntu groovy

 Gunroar is an excellent shooter in which the game environment turns to be
 the sea and your spaceship an armed boat. The player moves around in a
 level generated randomly, and containing enemy islands, turrets and
 enemy boats) and that never ends. Each enemy killed increments your
 points according to the time it took you to destroy it and its size.
 .
 Gunroar is another gem among many by Kenta Cho.