Mirror Mysteries is a rather mediocre FROG. Personally, I prefer FROGs over HOGs, so I might be a little biased in recommending the game. If you really like the genre, you may give this a try. If not, look elsewhere.
In any case, don't buy this at full price. It isn't worth it. I bought it at a big discount, and I feel I got my money's worth.
The game in detail:
# It has only one game mode. It's fairly easy, and the hint button recharges quickly. There's a random clicking penalty, that doesn't really do much (you can still click; it just makes the screen harder to see).
# The graphics are decent, but not amazing. The HO scenes are clear, and the objects are big enough to be spotted. There's a magnifying glass feature, that I didn't use at all.
# It's quite short. It took me just 1.5 hours to finish it, and I read all the dialogues.
# I've encountered one bug: Whenever a steam message (like "Friend X did Y") popped up, the screen went black. The game didn't crash, though. Minimizing the game and maximizing it again fixed the issue - until the next message showed up.
# The story isn't very engaging. Some evil mirror trapped your kids, and you have to save them by retrieving missing mirror pieces. It felt quite bland to me, but it wasn't too bad. Overall, there isn't much of a story, anyway.
(Note: I can't say anything about sound or VOs, as I played it muted.)