I spent months only playing this game on my Amiga 600 and I knew every enemy pattern from memory. If you died you lost too many power ups to be able to survive the later levels so you basically needed the perfect run and complete the game without dying.
I thought there were only 4 levels and one day I did it and beat the boss on the 4th level only to discover there was a 5th level that I had never played. I didn't last long on that 5th level and due to the massive disappointment of not finishing the game with a perfect run when I thought I had I was never able to climb that mountain again. It might be over 30 years since that day but I really want to try and climb that mountain again and achieve the perfect run in what must be one of the only Team 17 games they never re-released. "Plasma Power Up"