Didn't notice the help section tbh so my bad. I only used the menu to restart when I erased my starter piston(3 different times) then promptly forgot it existed at all. For the hints, I'd say to redesign the menu button(placement, size, color), I think I was subconsciously assuming it was a button for save files, map gens, and what not. After using the menu to reset the map/game, I subconsciously mixed up with a window minimizer for the right side, not a normal response tbh but that's all I remembered, I was actually surprised I forgot there was a menu button until your reminder haha.
If the later versions are planned to be expanded a ton to accommodate multiplayer, I'd recommend to have a customizable map size. I actually prefer the small size simply because my potato pc almost always gets over-ran by games that keep developing and adding to the base games. Keeping maps small is my only stopgap for managing any chaos. I still remember a 'don't starve' world where a griefer lit up the entire forest plus the base, I had to abandon the server entirely because I kept dying without being able to help much, all my gear and valuables burnt up and even my backups.
Creative mode...not really what I'm looking for personally, half the fun in building complex machines is having to gather all the resources for the different components myself. It gives the machine an extra layer of meaning that keeps me engaged in the process. Without that sentimentality(?), I tend to drift away from the game as a whole. Happened on Terraria when someone gifted me the endgame mining ufo when I was just barely entering late game. Because I was gathering tons of resources(even ones I didn't have the right level tool for) using it, they lost enough inherent value that I just played the game less and less. I actually had an imaginary divide in my base of stuff I really liked and not so much, which just so happens to be the additions before and after I got the ufo.
Left it at 'renewable' to keep it open-ended, but the greatest examples would be like those found in the sky block mod. Creating resource chain loops that slowly generates more than you put in. Upgrading the chain so that it incrementally creates more.
Another way would be like villager trading, though that's...the most boring way as it incentivizes farming the currency instead of gathering the resources(y'know playing the actual game). Trading is best left for the real end game, where you already have all the resource farms, but want a way to gather specifics en masse for those megabuild projects, at that point in the game building more/bigger farms is the last thing you want to be doing.
I mentioned putting it all inside a unit, because it'd be a way to clean up clutter in the overworld. Putting resource farms inside units like 'Sandship: Crafting Factory' helps keep the performance up because you don't need to render the farms, just the recorded input/output rates.
Kinda hate to keep doing it but Minecraft mods have the most obvious solutions! For the visual aids, I'd recommend something like the Foundry or Create mods approach to multi-block structures. Essentially a step by step guide to block placement for the absolute basic version of each machine. Expanding/upscaling it to your needs would still require you to do the rest.
Moving a unit...should've been obvious to me, but then again I guess I was too focused on using Minecraft as the analog for all this. I was just assuming 'flying machines' and those like them to be the 'walker' mentioned in the synopsis. Up to that point in the mission chain, I figured the only interact-able thing units could do was output power and mine/piston, with the moving being done by another piston.
This problem is basically what I was meaning for the 'tutorial' zone to solve. I just plain didn't know that units could interact with the world. The piston animations reaching outside a unit should've been a clue, but looking at the videos in the help section I was genuinely surprised when wires and generators were popping out the block too!
Ah, as a clue of how 'potato' my pc is, it was struggling with some of the embedded videos because it tends to buffer the first few seconds...which some for some the videos was all they had or where the mechanically most interesting bits occurred. Hence why I prefer more diegetic versions like Minecraft's ancient city redstone room, or the modpacks with a guidebook. Thaumcraft's book that expands as you learn is even greater, it gives out info and explains things plus visual aids where it helps.
Finally would recommend that you check out Introversion software's fail masterclass series. I only checked out the spacebot one as it was the one I was personally interested in their thoughts on as of yet, but it was an overall very informative video about the thought/design process that even an established team goes through.
Spacebot had a fundamental flaw that none of them could point out, until this video of them dissecting it which was that the game eventually abandons the main draw of programming bots and shifts into a 4x style before ultimately turning into a terraforming idler. Though tbh, I think it was mainly because the rest of the team weren't engaged enough to even play it to at all and ever find out that flaw for the guy.