I eventually managed to do it! I like the varied tasks you need to complete before the rocket is done. I also like the time management required from the challenge panel having a 60 second cooldown between games.
To me this game has three major gameplay problems;
1. The elevator. That thing would ALWAYS be just leaving when I was ready to rise out of the pit, not only wasting my time but also being a frustration. If there was a way to control the elevator myself, I would only have myself to blame if it's in a bad spot, but as it stands it felt like a huge hindrance to my enjoyment.
2. The physics. Every time I'd try to bring the fuel container over, the cable would break and no longer need to pull the big fuel canister with it. One of the colored cables also did this weird disconnect thing and fell down into the pit (my favorite place to be). Those things need to be put under control. There was also one time I was carrying the how-to book up the elevator, and because it touched the wall of the elevator, it got stuck in it and I had to restart the run.
3. The item carrying system. For the big rocket fins in the pit, it didn't matter how they were oriented, so it didn't matter. For the cables and screwdriver on the other hand, getting them to be the right orientation was a big pain. A way to rotate your held item would help out a ton.
I can tell you put a lot of work into the environment here, and there's lots of 3d models you made for this. You did a good job with the level design, there's just some gameplay stuff that gets in the way of the player appreciating all the good parts.
For four days, this is really good. You should be proud!