So...this scenario was made quite some time ago (1997?) but it seems the conversion to Aleph One compatibility may have broken some things (or maybe they were already broken, I don't know).

And it's a shame because this is a pretty ambitious project that tried some things that I've never seen attempted before with the Marathon engine.

The first combat level starts you out with no health or ammo fighting troopers, hunters, and even a juggernaut in enclosed spaces. It was pretty unfair/hard, even on Normal difficulty. The pervasive lack of health, saves, and especially ammo becomes an issue later in the level, when you must stop an auto-destruct sequence from triggering by using grenades to smash some wiring. The idea is really cool, especially since if you're successful the computer console will display a big "OFF" message, but the execution sucked; I reached that area with almost no grenades!

In the next level, "Gemini B" I almost got soft locked because a door in the southeast corner of the map permanently closed which prevented access to parts of the level. This was after I accidentally fell off a platform that for some reason was set to only trigger once. I was however, able to find an alternate, if convoluted, route and complete the level.

There was also a juggernaut on this level that will completely ignore the player. However, if the player presses a switch it will create friendly drones that will attack the juggernaut. Creating allies is a cool concept, but once again the execution is flawed. If the neutral juggernaut is killed by the drones a new one will spawn in, and this time it will actually be hostile to the player!

"In Partibus infidelium" had some really clever level design, including a system of pressing switches to toggle teleporter destinations, which would be reflected in a nearby teleporter "flag" which was actually a series of cleverly placed paper thin platforms. This level had problems too, though. Parts of it seemed like they should be reachable, but weren't (the entire northeast part of the map). Plus, flooding the hangar bays with radioactive goo would kill the player, but not damage any of the hordes of Pfhor at all. Surely that could not be intentional?

This level also had a clever ambush with a semi-new enemy type.

"Taurus = torus" was a fun level with no problems.

I got soft locked on "Aquae Perturbae" apparently because there were two uplink slots, and if you do not put your uplink chip in the slots in the correct order you cannot proceed.

Softlocked again on the next level "Deep Doodoo." Also, some of the bobs on this level are also neutral, meaning that no one will attack them and they themselves will not attack.

A cool concept on "Gauntlet." You have to run across the map while getting showered with grenades. You can escape on a waiting spaceship that is well designed (it hovers, even!).

Although this campaign does have some interesting concepts, as of 2022 it is broken and you have a high chance of getting soft locked while playing.

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.