I want to write this review with a strong recommendation that you read it after you finish The House in Fata Morgana. I disagree with the "it can be enjoyed even by those unfamiliar with it" line in the description, as one of the sprites used is a character who's sprite is revealed more than halfway in The House in Fata Morgana. I feel strongly that you get a better grasp of who the characters are if you've played The House in Fata Morgana, since they are essentially the same characters, even the same sprites. After having read Fata Morgana, this feels like bonus content. Plus this game is way shorter than Fata Morgana (took me around 4 hours to complete), not that that is a bad thing - it's just that you get to spend a lot longer with the characters and really get to know who they are in Fata Morgana since they are using them again here for this story.
None of these opinions have been a jab at the story of Seventh Lair. I really enjoyed the story (albeit short) and it does have its own twists. It's a fun story, well maybe fun isn't the right word. It's a good story. I kind of wish the characters had new sprites - since after spending so much time with them in Fata Morgana, seeing them here for this purpose is kinda like seeing a bastardized version of your favorite characters and waters them down a bit.

IF you've played Fata Morgana PLEASE read this for an interesting experience to see another scenario with the same characters you know and love.

If you have not played Fata Morgana, I cannot really recommend Seventh Lair - since these characteres might come off as one dimensional without the emotional weight backed by Fata Morgana, not to mention the Fata Morgana spoiler character sprite.

Seventh Lair is a fun game, with fun twists, using the same people I love from Fata Morgana.