I'm lucky enough to have in my hands both a copy of WOTC's Waterdeep: Dragon Heist and also DM Guild's Blue Alley. Blue Alley slots easily into the options based Dragon Heist framework, where alternate options make this campaign structure quite replayable. Blue Alley will add an additional option for your party to choose from, ideal for those who dislike being "railroaded". Having this adventure in your arsenal will make you look like the amazing DM who thought of everything! In saying that, the adventure will work equally well in any city setting - it's nature is fantastic rather than urbane, and it will spark the imaginations of your players with it's devilish fantasy rather than involve them in deep intrigue.
"... everyone knows Blue Alley is a deathtrap ..."
This warning appears on page 2, suggesting that your party might want to get some adventuring under their belt if this is their first introduction to D&D. A party with their wits about them and who's blades have a few notches in them will be able to jump in at level 1. The cryptic nature of the adventure is the real adversary here, a challenge to the players' intellect rather than their melee damage output.
Episode 1 introduces some interesting NPCs who might become features in your campaign including the main character: Mirt. Episode 2 details the main challenge of the adventure, while Episode 3 provokes the party to consider the consequences of their actions. Appendix 1 reprints one creature from Volo's Guide to Monsters, the rest of the encounters require the Monster Manual. Appendix 2 has the single page map, while Appendix 3 provides some tips for the DM.
I haven't yet run this adventure, but my advice is that you read the puzzles and traps carefully, so that your players' screams of frustration are equally matched with their ecstatic squeals of triumph!
In summary Blue Alley will add immense value as a feature within your Waterdeep campaign.
Results of Play Through Sunday 10 March 2019 at Melb DDAL (Adventurers' League)
Party: 4 x level 3 adventurers (Storm Sorcerer, Celestial Warlock, Bard, Fighter).
Session Duration: 4 hours.
I spent a lot of time preparing for this session, and every moment of preparation paid off! I printed out the incredibly beautiful high res map on A3 for me as a guide alongside the module print out. I printed each monster stat so I didn't have to open my Monster Manual (in fact I left my Monster Manual at home to lighten the packing weight). I printed all the phrases of the riddle to hand out to the players as they found them. I wrote up the DDAL player rewards including magic item unlocks. The only preparation I didn't do was look up certain magical and spell effects, for which I resorted to the hardcovers during the session. I prepared the Waterdeep map to show them the exact location of Blue Alley - something that was a lot of fun to research.
The party found themselves very quickly highly engaged with this module, and were determined to leave no stone unturned. I kept the pace fairly quick to give them a chance to finish everything, but they only just managed to complete the primary objective in the four hours. However, I believe that they would be able to complete the adventure's bonus objectives within another hour or so. This adventure contains so much content densly packed within the pages, its very easy to underestimate it as the text is so economical. The players knew when to respect danger, so they were cautious to heed the warning signs, and to avoid most of the deadly situations. I rolled a d20 to see which items were tidied up by the cleanup crew, and a bag of sand and the fighter's shield were lost to oblivion. I got one player to map out the dungeon old school style which was in keeping with the overall theme of this adventure.
The result? Four adventurers with a healthy respect for the dungeon of Blue Alley!