Beat on the easiest difficulty. Unfortunately the game did not clearly indicate the difficulty level in the options and I thus found the game too easy. I used the plasma shield for the first level only to find out afterwards that each power up is only good for one level. I next used the comrade Fighters, Atomic missile, Mega beam Cannon, auto aim gun, laser, homing missile and photon torpedo for the last level.

Despite the ease I enjoyed the game. The music in the final level sounded a lot like Doom and I was gearing up for some epic fighting. Unfortunately it was a platforming level and the final boss died in one hit. Also I died lots due to failing at platforming. Disappointing!

Tried the beginning on the hardest difficulty and I think I'll play through again at some point on hardest. Great game with solid gameplay while the one use power-ups give some tactics.