"Invasion of the Vorticons" was a quite difficult game as a child, because the controls were not as responsive as with "Goodbye Galaxy", but I actually liked some of the monsters more and the energy blast of the weapon more than in "Goodbye Galaxy". Overall however, "Goodbye Galaxy" was the clear winner between the two though.
I played "Keen Dreams" years later, but I really disliked the stone throwing in an arc and enemies waking up after some time again. Level design also felt better in "Goodbye Galaxy". I never finished "Keen Dreams", but I often finished "Goodbye Galaxy".
At the time I knew no English (pre-primary school and early primary school time), so the texts made little sense to me, and I interpreted them in my own ways, trying to find words that look similar in my language.