I can honestly totally understand the negative reviews, but this scenario absolutely BLEW MY MIND with its plot, labyrinthine design and overall mysteriousness when I was roughly age 12. It is indeed VERY hard, and I'm honestly amazed it was so difficult to find where to go even though I've played it before and I'm 2 decades older now. Though it can be frustrating, in my opinion it is off the charts creatively and truly incorporates design choices I've never seen elsewhere, many devices I'd never have even considered despite developing for Marathon for my entire lifetime. To respond to what others have said - no, A1 didn't break the scenario, it already had its very inconvenient, unforgiving style and very difficult battles.
Note: I didn’t create this; Dr Mike Trinder did. All I did was to convert it to a format compatible with modern Aleph One.
Gemini Station (first complete release: July 9, 1997) is a partial conversion for Marathon Infinity with 12 total levels, though players may not see them all every time they play it. Two are secrets and three are brief exposition levels, so it has seven proper levels, of which six are very long. Seriously, they’re huge.
I haven’t played through the whole thing in a while, but it was extremely impressive when it came out; as far as I know, it was the first scenario to incorporate several mapmaking tricks like airlocks and programmable teleporters. I last replayed it two or three years ago and felt it still held up.
As far as I’m aware, the only versions previously available were incomplete conversions that came with a shapes patcher that only ran on MacOS (and I’m not even sure they ran with modern releases). This version includes the patched shapes file, so you don’t have to bother patching the shapes. All you need to do is select the map and the shapes in Marathon Infinity and you’re good. (Make sure to select the shapes!)
Apart from patching the shapes and converting the map to MacBinary format, I haven’t modified any of these files at all; the readmes are even still in Mac OS Roman. Hopefully Dr Trinder won’t mind me making his scenario accessible to modern players; several people have asked for it on Discord over the years, so I figured I’d save people the trouble in the future.
In any case, I strongly recommend this, especially if you haven’t played it. It’s probably in my top 10 Marathon scenarios of all time, and the only things keeping it out of the top 5 are its short length and its relative lack of original assets (there are no new sounds and not many new graphics). However, it still looks phenomenal, and its map design would probably still seem inventive today. The writing is also fantastic.
Note: Screenshots incorporate Goran Svensson’s HD walls & landscapes, Freeverse’s HD weapons, and in some cases W’rkncacnter’s BRUTAL MARATHON plugin. I only spent about twenty minutes on these – they’re probably nowhere near the best sights Gemini Station has to offer. (Also, you probably shouldn’t actually use these plugins with it – certain game functionality is highly likely to break or not look as intended.)