The character of Marcon Tinol was originally introduced in PFS 1-07 The Flooded King's Court, which remains of my favorite early modules to cut players' teeth on. It's got roleplay and silliness, some grim serious notes, combat in varying circumstances, exploration, and even ethical considerations! It also awards a boon depending on your players' choices, which supposedly will come in handy in a future module.
Now, Marcon has reappeared as the star of PFS 5-05 The Island of the Vibrant Dead; a follow-up, finally! Except it's not a follow-up. In fact, if Marcon wasn't present in the module, it would hold absolutely no relationship to PFS 1-07 at all. It actually feels like a weaker module for his inclusion- not because there is something inherently wrong with the character, but because the disconnect between modules is so extreme that the two are hardly related.
It tells us that any players that completed PFS 1-07 would have been involved with getting Marcon settled on this island, which is swell... but why wasn't THAT the module instead? Aside from hand-waving what could have been a very engaging sequel story to Marcon, it inherently assumes an ending to PFS 1-07.
The most galling thing of all, though, is the map. Mythos Dungeon has been used in a whopping two (2) modules: this one... and PFS 1-07 The Flooded King's Court. The ONLY other place that Marcon Tinol has appeared.
There's another side to the flip-map! There's so many other underground dungeon maps! How in the WORLD did this end up reusing the literal same one?
If you're looking at this module as a follow-up to the story of Marcon Tinol, it's not. Marcon being included is a disservice to the module and a disservice to Marcon Tinol as a conceptual character. This module reads like Marcon was included because somebody said "oh hey didn't we introduce a not-evil undead character before? let's just use him again", without actually going back and reading the source material. If he wasn't included, the map snafu wouldn't be a problem at all- and in fact, could be a fun call back, as both tombs and crypt were Aroden-related, which could be reflected by similar architecture choices.
As for the actual content? Well, let's cut over to the Ruins of Azlant (which, we're told, we can learn more about in Pathfinder Adventure Path #122, though there's no reason to as it's never made relevant), in the middle of nowhere, though luckily and conveniently connected via the Maze of the Open Road. The story is a little too straightforward to be a proper mystery, but otherwise it's a fine tale with some minor (and likely expected) twists. Removing Marcon Tinol from the story actually improves it, as he drops out of actively assisting the party less than halfway through the module and it allows you to ignore any relationship the module has to PFS 1-07.
I'm so very disappointed in this module. I was really excited to follow up on the story of Marcon Tinol. Instead, I got a half-assed inclusion to justify showcasing this random island that just so happens to be directly connected to the Maze despite never having been mentioned before. It's a fun idea that I'd like to explore properly, but in the meantime I'm just going to have to retool this whole module, either to make Marcon relevant (which is going to require replacing the map!), or to just rip Marcon out entirely. Two stars because it's salvageable.