Killer: I agree about the control. I think it would have been far better to center the player on the screen at all times. The movement really is irritating.
As for the AGA chipset, that is required in this game because it's using dual playfield mode with 4 planes (2 x 16 = 32 colours total). ECS Amigas can only handle 2 playfields of 3 bitplanes (2 x 8 = 16 colours total) without sprite tricks for more. The graphics would have to change significantly to allow more colours, although with some nice copperlists you could do something.
The other reason it needs AGA is that the sprites (for the score) are wider than 16 pixels, a feature not available on OCS Amigas. There are tricks to get around it (reusing the same sprites like Parasol Stars score panel) but if it's AGA only I guess there's no need.