A Zork prequel marked by seemingly-irreversible actions that you discover after the fact are trivial. Most of this strikes me as a high-level design problem, although it's so common it could even be intentional: you are offered many puzzles early on, some of which are insoluble until late in the game - but there's no reason to believe that, and advancing the game is one of those seemingly-irreversible actions that you expect to cut off access to the unsolved puzzles. This problem is confounded by the number of locked scenery objects that are just red herrings - doors and containers abound in room descriptions, and give standard unlocking prompts rather than an assurance that they're outside the scope of the game.
Aside from those red herrings, the implementation is often shallow. Many exits are unmentioned in the room descriptions, not shown on the included map, or both. The room descriptions are brief, but lack the attention to craft that distinguished a lot of the Infocom writing; there are also occasional grammar errors.
Some puzzles are simple, well-cued, and yet feel really clever. Others are from the "read object that tells you what to do; do it". Still others are of the form "make notes and pick up objects at the start of the game so that you can have them in the late game when there's no way to go back for them."
A few pros: Some clever automatic cueing (to supplement the extensive familiar I6 menu-driven help). GUE memorabilia. Large scope (c. 100 rooms). Some of the puzzle design is simple but feels really clever.
My thought: downloading this one is no more irreversible than SPOILER or SPOILER.