I first played this game a while ago. And I think it's a testament to the writing and the design that I remember it clearly, and playing it again held no surprises - other than being delighted once again by the conceit and by the writing.
It is very like Dual Transform, also by Plotkin: a jewel of a game, tiny but perfect in its simplicity. Like that game, Heliopause hints at vast worlds to explore but delivers only a fraction of them; like that game, the sense of freedom conveyed by the clever writing conceals a short plot that runs entirely on rails. But again like that game, the writing is so beautiful, conveying so much with such economy, that it gets away with it.
I can see why some people don't like this game and others like it. There is something distant and clinical about it: its beauty is remote and grand, not personal and intimate. But I love this sort of thing. The story is simple but memorable; the settings are stark and evocative. I'd love to play a game like this that combined this kind of writing and imagery with true freedom and immense scope, but until that game appears, I'm very happy with ones like this.