I ended up writing a rather negative review on this on PlanetPhillip. Sorry. I appreciate the amount of work that went into it, but it just wasn't fun.
Right from the start, the crane is a sluggish, unwieldy thing. There's no mystery to what the player has to do here - the problem is in the execution, and that's not a problem you want to have in a puzzle mod. You've probably lost the majority of players on this first puzzle alone.
I thought the robot NPC was neat, but his voice seemed very disinterested and bored. He reminded me a lot of the infamous Larry from The Citizen mod in terms of detachment. He isn't helpful either - I wanted to +use him to get hints or to make him repeat his directions, since they are so easy to miss and he'll never repeat them.
I didn't encounter another major issue until I reached the bit with the turntable and pipes. This puzzle made no sense to me. There's no feedback for whether or not I'm doing the right thing with the valves, or even how the valves relate to the turntable at all. Turned everything on. Turned everything off. Tried to mimic the diagram on the wall. Just didn't get it. Started turning random valves and stumbled into the solution. Still don't know what I did to accomplish this - not good.
The part with the exploding barrels was pretty cheap. I got the cart into a spot where I couldn't reverse it out without triggering the barrels, so I had to go back 3-4 autosaves.
The cart itself, as well as the scene where you have to jump between two moving carts - they all have weird clipping and momentum problems. The cart can never take a turn gracefully - it's always trying to push me off and I have to "fight it" around every corner. I feel you may have needed to enable the "HL1 Train" flag on the tracktrains to make this connection with the player more robust.
The train dodging sequence went on far too long. You could have easily cut 2-3 tracks without any impact. Again, much like the exploding barrels, the player is inevitably going to get killed the first time because there's no discernible strategy here. You either stop and wait, or you get killed. I think you even had the trains going back and forth on the same stretch of track as well, which didn't make any sense. Neither did the houses that moved up and down(
) during that last, very long platforming segment.
As you can probably infer, throughout the mod, the punishment for failure is needlessly heavy-handed. There were also parts where I could see outside the world and encounter invisible walls, especially around the pipe puzzle.
I can easily see the time and effort you put into this. But, I think there were some relatively simple, practical things you could have done to improve this mod before releasing it. Hopefully, you'll listen to some of the feedback and make improvements.
You've put a lot of work into this - it's that last part that takes the longest to get right. I think it's easy to see that the moral of the story is that you needed to have people testing this way sooner in the process.