Is this the sequel to Zenkai?
Presumably it is, but exactly how is unclear; it's not like the first game appeared to have any story, and this is really a completely different sort of game. You play a mecha with a jetpack, moving with the arrow keys (5 on the numpad changes facing) including a recharging jetpack. A and S fire homing rockets out of the fore and aft, and D fires your beam, which is the only limitless ammo weapon you have. In contrast to the previous game, you can take quite a few hits before dying.