An interesting, different kind of low-level adventure without as many of the horrific death traps that occurred in modules of the early 80s. The party doesn't know it, but they are on a quest for a magical artifact and along the way will face a variety of monsters from the 1st edition Fiend Folio. The monster selection makes it readily apparent that they designers were trying to use Fiend Folio monsters, and they are pretty successful in doing so. I would say this is a reasonably playable module and a quick read.
So a group of friends and I just finished The Sentinel (last year we had a nostalgic interest in playing some good 'ol old school D&D and started with a Basic D&D campaign and have since transitioned it to an AD&D 1st Ed. One). At first I thought this adventure was a little mundane with a run of the mill plot, some basic subpar enemies and challenges and our group had little trouble hacking and slashing through on their way to victory. I was pleasantly surprised at the end of the adventure when the Sentinel is revealed and the actual villain that awaits. I'm actually excited to see how the next module proceeds. My cleric, Cassius, stands ready to vanquish this foul evil from the land.