Disclaimer: I'd give it a 3.5/5, but it doesn't deserve a 4 in my opinion
SandStorm starts out quite interesting, and has a nice story. The LIs are each gorgeous in her own way. I like how all characters are different from one another, and how their personality directly influences the story and outcomes.
Most of the time, the story is interesting, even intriguing. However, at some point it just... Stops? Things get going, you start figuring out the Mystery, getting to know the characters, the LIs on a deeper level, and all of a sudden that's it - you're stuck with this and this ending, goodbye, go play SnowStorm.
For me, the abrupt ending (Rion & Nora) and its fan-service additional scene really spoiled the quality of the overall story, so I loaded a previous save to see what happens if I make some other choices. And even though it does give some additional answers to the Mystery, it's still underwhelming.
Hopefully SnowStorm will be better in this regard.
PS: I loved the music in this one, really nice