A great sense of exploration in this one! I feel a lot of Portal inspiration here and you've done a good job of having that some vibe, having the player make their way through a dilapidated facility with just enough functioning parts to progress forward.
The controls are over all, placing cubes could be a bit iffy sometimes but usually only when I was actively trying to break the system. Speaking of, I did manage to do some things which felt unintended, like grabbing a power cube out of its socket once I'd gone through the door it powered and dragging it with me. That was a high risk, high reward situation since it did lock me in, fortunately I had enough cubes with me to get to the end!
I'm not sure why ARGO is vulnerable to gas clouds or why giant spiders want to eat it so badly, but I greatly enjoy that the answer to such problems is to blow them up with an infinite grenade launcher. :D
It's also nice to know that Tim's robot building hobby will eventually lead to the salvation of humanity from the [Lost Data]!