This game looks quite cool, have to give it a try. It's not the oldest game of it's kind though. I remember playing a game called Styx, made by Windmill software in 1983. Lousy CGA graphics, PC speaker, 5 1/4 floppies, no hard disk. Ah, the memories.
Hey, I just noticed Styx is also featured on Abandonia :
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I think it should appear on the similar games list, no ?