Enigma Fellowship: The Submerged Sentinel

An experimental submarine, the ISS Sentinel, carrying a revolutionary new energy device and the world’s leading scientific experts has missed several scheduled check-ins. The Enigma Fellowship has been contacted for help. Given the lives and scientific knowledge at stake your mission is to not only find the submarine but also rescue the crew.

Rating: Tricky!
Completion Time: 2.5+ hours
Date Played: 4th April 2021
Party Size: 1
Recommended For: Folks who want a challenge at home!

Okay so first things first… I genuinely think I’m not smart enough for Enigma Fellowship sometimes *nervous sweating*. Which is why this game took me well over 2 hours (the website recommends 180 minutes… ok ok so not too terrible), but I did take several breaks and used way too many hints. But long story short, this one for me, was a real challenge. You can check out my experience of the earlier games in the series here:

  • The Lost Knowledge – played it in December 2020 and had a pretty good run with it! Don’t remember using too many hints and we aced it in under 2 hours
  • The Scattered Cards – a post-Christmas murder mystery and tricky, but not impossible!

For a first in the Enigma Fellowship series I tackled this one was a team of 1, sitting down on a sunny Sunday morning (Easter, no less!) around the table with a couple of snacks. So here’s how the game went…

The Story

The best thing about The Submerged Sentinel is the story – it’s so exciting! The game(s) have the unusual style of second person narrative “you open this, you are surprised, you hear a letter through your door” but from start to finish I found myself gripped and wanting to know what happens next. The ending too… Ahh, it’s hard to talk about it without giving too much away, but gosh! That twist! I love a twisty ending, and this escape game has buckets of twists.

A mysterious letter arrives and due to the sensitive nature of the information, all the steps you need to take are hidden carefully. First, you must access a login, and from there you must travel to board the EMS Investigator ship to search for the submerged sentinel and unravel the mystery.

The Experience

Enigma Fellowship games are played with a combination of physical paper material and an online interface. You start with an envelope and by scanning QR codes access each of the ‘areas’ with a password you must input online. Most envelopes contain even further envelopes to be opened, giving the sense of gatekeeping between each puzzle and making sure you pace yourselves appropriately with the story.

It’s extra exciting opening a new envelope and rummaging through the things you find inside, and genuinely I think it’s pretty close to a real life escape room experience with more than one area… You find a key, unlock a door, and boom! So many more puzzles.

The Puzzles

The Submerged Sentinel has an 80% difficulty warning on their website and they’re not wrong. I chatted to a fellow reviewer the other day about a few games we had differing opinions on the difficulty of… Sometimes puzzles just ‘click’ and other times you’re staring at something confused for hours. So whilst The Submerged Sentinel is probably not an objectively difficult game, I just couldn’t get my head it.

What I mean is, I think I used at least one hint on every puzzle and in more than one puzzle I had to ask for the answer. It’s a super good job the clue system is so detailed and robust. There are typically 3-10 ‘hints’ before finally giving the answer, so you’ll get the nudge you need!

One thing to highlight is that most of the puzzles in this game are multi-step. You spot something in the text, then convert it to something else, then flip something on it’s head, the fold something, then translate it back into something else and so on… This means there’s a lot to do per puzzle. I’m always impressed by such a small envelope (it fits through your letterbox and doesn’t feel heavy) contains SO MUCH CONTENT. In a content-per-page, Enigma Fellowship wins hands down! Fantastic value for money.

As a whole, players can expect to encounter some of the following types of puzzle: As it’s shipping themed, you bet you’ll need flag codes, semaphore, ciphers and Morse code! The envelope also comes with a black light which is used several times throughout the game in very clever ways (the second black light puzzle made me exclaim with delight when I figured out what to do!), there’s a couple of maths puzzles, and a few that also involve the use of maps. In short – a good mix. Again, there is so much to do.


I am always impressed by Enigma Fellowship and I think the creators Anuj and Orsi deserve all the praise in the world for the amazing series they’ve created. Each game is packed with love and care, and they really go the extra mile to listen to customer feedback and improve their games. Sure, I found this really hard, but heck sometimes I need a challenge! I’m becoming complacent in my old age *cough cough at my 25th birthday coming up* and I’ve gotta keep my wits sharp with a bit of submarine subterfuge.

The Submerged Sentinel can be purchased for $22 USD on Enigma Fellowship’s website here.


  • Mairi is the editor-in-chief of The Escape Roomer and covers escape room news and reviews across the UK's South.

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