The book in question is The Video Games Guide by Matt Fox, and seems to have been written and/or published in 2006. It's obviously a British publication, because reviews of ZX Spectrum games are especially prominent. In the middle of the book is a full color gallery of all the games that got a five star rating, most of which seem to have been graded on historical significance more than actual quality. I was quite embarrassed at first not to recognize where its screenshot of Doom was from. It was obviously somewhere in Episode 3, but I couldn't recall any setup quite like it. And it wasn't like it'd be taken from some PWAD or another... right? But when I went through that episode with no monsters the next morning, I couldn't find any matches. The author may have got all these screenshots from Google Images or something. So now I'm going to share it here to see if it looks familiar to anyone else.
Please forgive the quality. It was quite a big book, so I thought scanning would be too much hassle and took a photo. I feel like the simplicity and relative competence place it somewhere in '94 or '95.