I really love the presentation and mood, and the writing is so damn good. It plays good too, basically feels like old Doom but they do a lot of fun stuff with its implementation of free aim. Some levels are very questionable in design but most are fine and for every level there are walkthroughs available so I don't think its a deal breaker. Would've been a 4.5 for me if the ending had been a little stronger, just feels kinda cliffhanger-y.

Edit: spoiler territory okay don't read on if you don't wanna know but:
Thinking a bit more about the ending I find myself appreciating it more and more. The entire time Durandal has been playing you and the ending isn't you overcoming him or confronting him or anything, he gets exactly what he was aiming for the entire time and it makes sense too, he's the brain you're the brawn, he feels incredibly powerful the entire story despite realistically just being text on a black background and they actively choose not to diminish his power at the end and instead reinforce it by having things go his way.