I picked up The Sanctuary Ruin because I wanted a small encounter area (a side trek, if you will) as the PCs traveled to the main area. A place for them to pick up some experience and some treasure, because the next adventure will be a bit tough for them if they go into it at their current level. I don't think I'll be disappointed.
Some spoilers may follow.
The module reminds me of a very small Keep on the Borderlands. A goblin warren is described, along with the "home base" for this adventure, although many details the home base are left to the GM.
The goblins are presented with alternate actions, depending on what the PCs do. For example, if a large number of goblins are killed, the remaining goblins will harvest poisonous mushrooms and drop them in the inn's water supply. Goblin reinforcements are mentioned as well, moving from one area to the decimated area. These details help GMs make the game world seem more alive, that critters don't just wait around for the PCs to slaughter them. Furthermore, there is an outside group exerting pressure on the goblins, and the goblins are plotting revenge. Enterprising PCs (and perceptive players) could find a way to use this to thier advantage.
There are two issues I have with the adventure. First, the random encounters are very difficult for a low-level group to survive. A 1-in-6 chance of an encounter every hour wandering the woods means over the course of a day, a party will have 4 encounters. The first entry on the random encounter table is "d4 giant toads." I will be modifying this for my own game. Second, there is a very real possibility the PCs will be overwhelmed by the goblins. This resembles adventures like B2 The Keep on the Borderlands, but that wasn't my favorite part of the module. It will require some thinking on the players' part to accomplish the destruction of this goblin tribe.
A final quibble: the initial encounter describes a wagon peppered with arrows, and a band of goblins victorious in their raid. But the goblin equipment described doesn't mention bows or arrows.
I like the interactive nature of this module. I like that it is generic enough for me to place where I need it, with minimal backstory. I believe reckless PCs meet their dooms. I would have liked a little more development of the PCs home base. But this is a very good module, and I'm very pleased with my purchase. Overall, then, I'll give this module 4 stars.