Before embarking on Simply Phobos in 2004, Paul Corfiatis was no stranger to kickin' out the love for Phobos-themed maps. Some of these ended up in The Twilight Zone and The Twilight Zone II megaWADs, but this map marks Paul's first standalone Romeroian excursion. Toxin Refinery is an imaginatively-titled remake of the original Doom's E1M3, released in 1999 along with a bunch of other odds and sods. Also, like a "Bad Dream", it's got a secret level for the secret exit; more fun in the Martian sun. I'm guessing that the bonus level's name is "Magna", since it's written into the level geometry.
As one of the /idgames reviews succinctly points out, Toxin Refinery is more or less a mashup of elements belonging to both Doom's E1M3 ("Toxin Refinery") and E1M6 ("Central Processing") with perhaps a bit of E1M9 as a garnish. They're not cut and pastes, and Paul has added his own particular interpretation. The toxic crossways from E1M6's southeast area factor heavily into Toxin's southern area, for instance, but Paul has used the corners of the chambers as staging areas for an organic invasion by demons, perhaps my favorite encounter out of the whole level since the pressure is very real.
The great outdoor walkway from E1M6 joins the E1M3 section up with the southern crossways. It's the scene of some light action, but your return trip opens up several balconies thick with imps. Not the sort of thing you'll want to stick around to whittle down with the shotgun or chaingun, but you might walk back with the glut of rockets from the secret exit. The "Toxin Refinery" area includes the starting area - the raisable walkway now leading to the normal exit - and a remix of the donut / key segment from E1M3's north. The pit is now the centerpiece, though, brandishing the yellow key, and the area is the scene of a massive demon slaughter.
I'm talking true horde shit, like whip out the chainsaw and back into a corner until you've weathered the storm type stuff. I actually forgot about the chainsaw during my playthrough; the monster closet caught me off-guard and I was just wiggling with the shotgun until I could break free. breaking the key plane just makes things worse since there's a teleport ambush to add insult to injury, but if you manage to thin out the first crowd, you should be able to easily handle the first. The rest of the monsters barely even register, even the Barons, given the ubiquitous demons.
As a Phobos remix level, I like the cut of Toxin Refinery's jib. All the moving sector parts to get to the secret exit are pretty cool - like the timed door secret area with the tech guts closet with a yellow key lock on it. "Dang," you think. "Must be important." There's also the bit with the soul sphere, with the columns that lower to form a sort of impromptu staircase. I'm so used to seeing things raise up from the floor to make stairs of any kind; doing it this way is a nice change of pace. I am hoping that Simply Phobos offers some more Things Not Yet Seen, but this is a pretty fun diversion. I also dig the music, penned for this occasion.
"Magna" is secret level to the core. It has a lot of Barons, a handful of zombies, and a bunch of barrels strategically placed as spoilers. The action is actually pretty intense in spite of all those soul spheres lying around since opening the first door and firing the first shot will cause just about all of the monsters on the map to head toward your direction; the hesitant marine won't pass. There probably won't be anything left in the toxic tunnels once you're done, but given the free-flowing layout, you never know what might sneak up on you. E1M9's music is silly, as described in the .TXT, careening back and forth between a bagpipe rendition of "Amazing Grace" and "Overworld Theme 2" from Super Mario Bros. 3.
If you're looking for a little Phobosian adventure but don't want to commit to a full episode, I think that you'll get your fix from Toxin Refinery. If you can't stomach seeing E1 "homages", well, I'm sorry. You could always try the secret level!
'TWAS GRACE THAT TAUGHT MY HEART TO FEAR
AND GRACE MY FEARS RELIEVED
HOW PRECIOUS DID THAT GRACE APPEAR
THE HOUR I FIRST BELIEVED