NOTE: This review was written for version Gold and may be outdated.
Edit: I've just been reminded of a few things worth pointing out, so I've edited the review slightly.

Ah, Labrynth of Zeux [sic]... the odd-man out of the series, due to it being a standalone release rather than a MegaZeux world... Let me start by saying that when I first heard that Lachesis and company were remaking the entire original game for MegaZeux, I flipped! I'd always loved the original version -- so much so that I went to the trouble to register it, alongside my copy of Code Red -- but never actually sat down and beat it legitimately. Something about the classic CMF music and the relative simplicity of the game had me enchanted right from the get-go. I even had a little world in the works way back when I was young and impressionable. That world is long gone by now, as are the days of MS-DOS, but thanks to Lachesis and company, people can experience the magic that they may have missed due to the relative obscurity of the title.

For those unfamiliar with the game, it's basically your average MegaZeux side-scrolling game, but was made before MegaZeux had side-scrollers. (Or even existed!) In it, you play Vince M. Louis, Theologist, in his search for the mystical Staff of Zeux. Gameplay is relatively simple. Arrow keys move you and you can use bombs to blow things up when you have them. But that's where the simplicity ends. Software Visions put a lot of work into the original game, making sure levels were all solvable as well as being unique from each other and intriguing to the player. The game as a whole is one very large combination obstacle course, reflex test, and puzzle box all played from a 2D perspective. And this port of Labrynth of Zeux hold true to these principles.
The controls are the same, the physics are roughly the same, the enemies and obstacles are the same, and even the graphics and effects are the same! The core gameplay and engine is almost entirely indistinguishable from the original MS-DOS game. Lachesis and company did a fantastic job of porting everything and making sure players were almost unaware that they were playing anything other than Labrynth of Zeux. However, there are several changes that have been made as well!

Gone are the old CMF files which the original game used. No longer will you hear Captain America and Spider-Man in Dr. Doom's Revenge playing on the title screen and game over screen, nor Dungo from Jill of the Jungle in some levels. No more Rock Me Amadeus, no more Crowley... In fact, almost nothing remains of the original soundtrack... in the default world. Lachesis' team thought ahead and included OGGs of the original tunes for people to use in their own level packs, or just to listen to. Or so I thought. As I recently learned, there's also an alternate game world included in the game, "ZeuxOST", which lets you play the game with the original soundtrack -- a mostly undocumented feature! In addition, an arrangement of the title theme from Dr. Doom's Revenge does make a brief appearance at some point in the game. But I digress.
Rather than the old mixed bag soundtrack from the original, 50+ brand new songs (and a couple very awesome remixes of familiar tunes) have been placed into the game! Every single tune sounds utterly fantastic and matches each level perfectly. You may find yourself sitting in a level or pausing the game just to admire the soundtrack. It's kind of a shame that loading a save game causes the song to restart, but you can't fault Lachesis for that, as that's a common MegaZeux trait. Luckily, all songs have been saved in the ever-convenient Impulse Tracker format, which makes listening to the tracks on loop or individually quite easy. Admittedly, it would have been nice if more of the old soundtrack had been given remixes, but I'm certainly not complaining about what we got!
The game also replaces all of the original PC Speaker sound effects with brand new ones, also created in Impulse Tracker, but saved as individual OGGs. The new sound effects are just as memorable as the old ones and range from beeps and blips to a single utterance of "Yeah!" when you beat a level. Explosions sound good, there's a unique sound for jumping underwater, and all and all, everything sounds as it should.

To the best of my knowledge, every single level is both intact and unchanged from the original. Now, this does mean one particular level gives you a completely useless clue (which are keyboard shortcuts which mostly don't work) but as far as I notice, it was just that one level. It also means What this means is that the levels are just as hard as they were in the original version, which means you will probably be saving and loading a lot (as suggested in the last batch of paragraphs). Unless you're a purist. In which case, Lachesis has you covered.
Once you've beaten a level, it becomes enabled on the convenient Level Select menu. This in essence gives you infinite continues at the price of a much lower score and gem count, but is also very good if you just want to practice one level over and over again.

Now, I said that the game was perfectly spot-on as far as physics and gameplay, right? Well, I somewhat lied. The basic movement and physics are still intact from the old game, but Lachesis has improved on a few aspects that bugged players of the original game. A couple of things had to do with climbable tiles. It was impossible for Vince to jump from the bottom or ladders, vines, or poles, as well as the edge of conveyor belts (?!) in the original version unless there was ground directly beneath him. This version of the game fixes these oversights. In addition, Vince can now jump if he's standing on a ground-level pole tile.
Another minor problem with the original game had to do with the Missile Launchers. First and foremost, they were prone to just dump missiles out at alarming and often self-destructive rates. For another, they didn't give you any warning whatsoever as to when they were able to fire. Lachesis fixed both these problems, putting a higher minimum delay between shots as well as not only a visual cue, but an audible cue before they fire off a missile.
If you've played the original, you might remember that if you push a physics-enabled object out from another physics-enabled object -- let's say a metal crate out from under a wooden one -- the object above Vince would crush Vince to death. Lachesis gave people a fantastic option, "Safe Push", which resolves this. With this turned on, it becomes impossible for Vince to push or grab any object which is sitting directly beneath a physics-enabled object.
And lastly, Lachesis fixed a very minor problem with levels that lacked a proper floor. In the original, Vince would fall into the scrolling text bar if there was no floor, but he would erase the scrolling text as he moved through it! This is not so in this version of the game. Vince simply hides behind the scrolling text now without disturbing it in the slightest.

With all these fixes came some things which I wish hadn't been changed. For starters, the way Vince jumps has been fixed. In the original, holding the jump button would make Vince jump over and over again, but it also made it look like Vince wasn't touching the ground when he landed. He could still be hurt by landing on certain things, so it was just a visual error... which has been fixed in this version of the game with no change to the physics whatsoever.
The other thing that was "fixed" is that Vince no longer rotates in place when idle. In fact, he has no idle animation at all. I sorely miss watching Vince spin around for no apparent reason and question why Lachesis decided to remove that particular aspect of the game. As it turns out, Lachesis is going to make Vince spin around for his idle animation with the final version of Labyrinth of Zeux: Platinum Edition is released! My apologies!

Finally, Labyrinth of Zeux includes a level editor, much like the original game did, though the level editor here is built right into the main world. I haven't played around with it much, but it seems fairly similar to the original, but with additional features and functions to make level editing all the easier.

All and all, Labyrinth of Zeux does some real justice to the source material without disturbing it too much. It really would have been nice, albeit somewhat inaccurate to the original game, if the movement controls had been tightened up a little more and certain aspects, such as riding Bombers, had been made easier, but this just adds to the authenticity of the port. It says a world of Lachesis that she kept some of the random quirks of the original game in. Having played both versions extensively, I once again reinforce the fact that it's almost impossible to tell the difference between Lachesis' version of the game and Janson's original version. Or rather, it feels like you're playing v3.00 of the original game rather than an unofficial port written in a completely different engine. And that, to me, makes this a fantastic port and very worthy download.