This is a lovely adventure, and a wonderful first effort for Baldman Games. The introduction of a modrun adventure is fantastic and something completely unexplored in previous 5e content. The puzzles in the adventure are amusing and engaging, unlike the silly one in DDEX2-1. The combat encounters are rather light and unintimidating, but the mystery and the places it takes the characters are memorable and very fun.
With the perspective of a stickler for rules, one might criticize the chase sequence at the end of the adventure, as one other reviewer has done. It is a very fluffy encounter, designed more to dazzle players with the eccentricity and wonder of the many realms than to provide a real or meaningful challenge, but it is still quite cool. On a technical level, it might be hard for an inexperienced DM to keep a straight face during the chase, knowing that no matter how many arrows the players shoot at the baddy, it won't matter, but still, it's just a great bit of colorful fluff.
The only real criticism I have of this adventure is that it doesn't tend to run 4 hours. Unless the players really struggle with the puzzles, since the combat encounters are so light, it tends to clock in at around 2.5 hours. Apart from that, bravo!
[5 of 5 Stars!]