Gunroar

Gunroar is a freeware, open-source vertical shooter with abstract vector
graphics created by famous Japanese developer Kenta Cho. The player controls a
ship resembling a jetboat seen from above, trailing around the screen and
shooting an endless stream of bullets against the enemies, while deftly
avoiding collision with their incoming projectiles. The main weapon keeps
automatically shooting as long as the button is pressed down, while the
secondary missile weapon has to be launched by activating the trigger every
time. A countdown clock at the upper left shows the remaining time before the
arrival of the next large boss enemy.

Gunroar