In its prime (Seasons 1-5, with Season 4 to me being the best and most consistent season with a lot of classic episodes and even the weakest episodes being far from awful) 'Criminal Minds' was one of my favourite shows. From Season 6 it did become hit and miss, with the odd gem, but a lot of average episodes and some stinkers.
Season 12 has been an inconsistent season but has been nowhere near as underwhelming as Season 11. The best episodes of Season 12 ("Spencer", "Elliot's Pond" and "Mirror Image") are not classic/elite, while the worst ones ("True North", "The Anti-Terror Squad" and "Hell's Kitchen") are not bad enough to be stinkers/low-points. "Unforgettable" fits in neither extreme, somewhere in the middle as far Season 12 goes though much better than "True North".
Visually, the episode looks great as to be expected. Very well shot and lit and is overall stylish, gritty, classy and atmospheric. The music is moody in the haunting and melancholic sense and fits well, without either enhancing or distracting from it. The direction is alert, tense and accommodating.
The acting is very good, masterclass quality in the cases of Matthew Gray Gubler and Jane Lynch. Their chemistry is very touching here, and Diana's dialogue about coming to terms with her illness is heart-wrenching but also inspirational. The writing is of uneven quality but their scenes were written beauty.
Finally, Walker is more interesting, with a well-interwoven back-story that proves essential to the case and his chemistry with Sam also resonates strongly. The team work cohesively, together and with proper investigation, their concern for Reid also notable.
However, the case itself is pretty humdrum and lacks tension and suspense. It also ends on an incredibly anti-climactic and rushed note, even for 'Criminal Minds'.
As much as Reid is one of my favourite characters on the show, him and Rossi nowadays are my favourites, the prison subplot started off really well but now feels like it has gone on too long and has felt eventually too drawn out over the season, by the end of the episode the subplot was practically begging for a resolution.
In conclusion, not bad but not one's definition of unforgettable. 6/10 Bethany Cox