Please note that this review is organized from bad to good.
The biggest problem I see is also something that people who have not purchased the game will have noticed: it is extremely expensive. Nearly 30 cents per page is rather extreme, given that many very good RPGs are sold at 10 cents per page, sometimes even less. So, this is an investment you should probably think about.
Contentwise, the biggest problem I faced was with the structuring of the rules, which at places felt counter-intuitive. Mind you, it is not anywhere near the rules of Level 7:Escape in that regard, but I feel that it makes it unnecessarily difficult during the first sessions. Like, for instance, that you can search for secret rooms only after facing the PEF that is automatically generated for any room - but the rules first give you explanations about secret rooms and then the PEF information - which can possibly get important for you much earlier than the secret rooms. Likewise, a few clarifications or maybe even repetitions at times would have been helpful. Traps can be generated by PEFs, but the only information about them is given for traps generated in a special type of secret room.
Some rules are rather sketchy, as for instance the melee rules - it seems that once a character starts melee, that single melee has to be done to the end before other melees can be handled. And how you can get into multicharacter melees is left somewhat sketchy.
The absence of a character sheet is also disappointing given the high price and small size of the book. Surely, there would have been space for one more page. And the way characters are created and handled, designing such a character sheet would have been feasible, I think.
"Grunt" is used ambiguously - defined as any NPCs early on, but later on also any non-leaders of the group (which could also be PCs). In my eyes, a rather unnecessarily confusing word choice.
Not as much of a problem, there is another tidbit that can confuse people on the first reading of the book: in several places, the word "table" is omitted when telling the reader to consult one of the tables that are placed at the end of the book. Until you notice the omission, this is rather confusing as the main tables have the same title as the sections they belong to.
A very slight negative in my book, as it is about optional content, is the lack of variation for traps and lack of theming for rooms or secret rooms (there are different secret rooms, but they are not themed as the minions).
Personally, I didn't find the stop boxes at the ends of sections as helpful as intended most of the time. A detailed step-by-step example of a somewhat more complex fight would have been really helpful in my eyes.
In addition, I like to start with insignificant youngsters who may have a spark but not yet the experience, and the system advices you to use a character that is defined as an experienced adventurer (although this is mostly fluff, so you may ignore it).
It is a little sad that levelling up quickly becomes meaningless because of that (your starting adventurer is supposed to be REP 5, and REP 7+ is already said to be legendary).
On the plus side, the book is very light on the ink, making it easy and cheap to print. Typeface is clear and readable as are the tables.
The dungeon generator is simple but seems well-balanced. It is also easy to use.
The rules in general are rather simple and straightforward, although initially, you may have to check out a few situations to really make them click.
All the tables are placed in the back of the book, which is a very good design decision as it makes playing the game easier once you have grasped the basic rules and don't need to reference the text proper.
The game really shines in my eyes in three nice aspects:
First of all, there are four different missions that may be the cause of your dungeon crawl, killing the boss monster or getting the treasure being only two of them. Thus, combat may actually be something you don't need to fulfill your mission.
Secondly, there are several different bosses (10 if I counted correctly), one of which is selected randomly at the start of the game taking also your general power level into account (okay, only slightly, but still). Whenever you encounter monsters in the dungeon, which monsters you encounter is influenced by who the boss is; unless you meet a rival adventuring party...
Thirdly, the PEF system is really great, adding a dynamic element to the crawl. Enemies do not simply sit in a room waiting for your crew to burst through the door (okay, some of them do that as well), but they move through the dungeon and hunt you down as well. And the rules for that are extremely simple.
All in all, the game is a lot of fun as a solo dungeon crawl with many neat details despite playing very quickly and simple. The different missions and boss-based minions give a good sense of theme while the PEF system adds a lot of suspense and foreboding to the game.
However, it is, at its heart a dungeon crawler, but definitely one of the best I have come across. Personally, I found it worth the investment despite the rather tall price tag.