I really enjoyed the look and feel of these maps. They are impressive in size and detail and the story is well-written, even if predictable.
Here are some minor observations though:
1) The scenario doesn't seem to be balanced for Total Carnage, as there were many moments when I had completely ran out of ammo, I had to bump the difficulty down a notch to make it bearable.
2) There seem to be some minor visual glitches and issues in some parts, I don't know if it's because of the conversion or original bugs of the scenario itself. I haven't played with any plugins, and I used the OpenGL rendering.
Almost all of them seem to be present in Deep Doodoo, where certain walls display what Doom players refer to as a "halls of mirrors" effect, quoting the Doom wiki: "a shimmering mass is visible in the empty space outside, composed of parts of previous frames of animation".
The airlock that connects the normal and underwater sections also suffers from this, in fact it's acting in reverse from what I can tell, since the room gets flooded when the underwater section is closed and becomes breathing-friendly when the door leading to the flooded reservoir is open (which is both taller than the airlock and filled to the top with water).
Another issue for me was that during the first playthrough, I got softlocked on Aquae Perturbae. I think I grabbed an uplink chip earlier than the game would've wanted me to, because no matter what I did, I couldn't place it in one of the slots, no access hatch was opened and I couldn't progress, this was aggravated by the fact there's no spoiler guide available, so I kept wandering for about an hour before I loaded an earlier save and was able to finish the level. Aquae Perturbae also sometimes crashed the game, but it seems to have only happened when the level got bugged.
So both of these levels seem to have some issues. I haven't noticed anything else so far, but I just played it once, so it's possible I might miss some other bugs or glitches.
Edit: found one more bug, on The Gauntlet reloading the fusion pistol is broken, your ammo gets set to 1 shot after reloading.
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.)