Which parts were frustrating for your players? Seems to me that many of the situations had multiple solutions. It is the players job to come up with ideas and it's the DM's job to adjudicate in a reasonable and fun way.
Now maybe your players are used to everything being easy and/or they don't like traps? This old-school dungeons rewards cautious, thoughtful players. And if the DM appropriately tips/hints, then the traps/challenges need not be a big issue.
In my opinion, this is a great starter dungeon for a new DM and group. Easy to run. And if the players don't know what they are doing... well they'll learn the hard way!
Indeed, my players were not used to certain things that you yourself point out this dungeon requires. Why? Because it was the first time they had ever played. And, of course, you can imagine different solutions to any challenge, even choose not to use it or replace it with another one. But I prefer it when an adventure gives you some ideas.
Do you think differently? Perfect—write a positive review and give it a high score, but allow me the indulgence of having my own opinion about what I like and what doesn’t convince me after 34 years of playing and running games, without needing anyone to explain to me how one is supposedly meant to play a role-playing game.