Oh, this one is - IMHO - a bit unfortunate: 

Because the writing is solid, good quality (on the technical level: flow and syntax and conciseness and all that) (and with some character, too); well built, implemented, and with good 'flow' from place to place; there's also a good amount of content and a help system...  

it's just a bit dull though. 

E.g. (and without spoilers) 'the fourth room': the exits are hidden behind corners, exciting, it connects to 'the early area', interesting, I'm still feeling apprehensive over my brand new situation.... but there's nothing of note in it.

 Or, the area between the prison and the military complex. That's nice, a bit of surprise, bit of danger, took me '10 seconds' to even get there, and the sediment has its own description, too.... but then nothing in particular happens there. 

After that, we get a brief memory flashback for the character. Maybe we'll learn some more about them later, would be interesting and help the player feel more invested in them...

There are also entire rooms where the description goes out of its way to say that it's bland and basic and featureless, and nothing is to be found there. 

Like, if one wanted a 'hotfix', imagine the character having some interior monologue about why things are this way, what might have happened here before, and what might (have to) happen next. That would IMO go a long way to add suspense (and give the character some more depth). And maybe one more smaller puzzle in areas that otherwise have nothing in them (or cut/ replace some of them)