Pretty cool, I like the 3D environments, machine animations, and goofy voicelines for the workers. Some parts are a bit too abstract, like when I get coins for putting cubes into the extraction machine it doesn't make much sense. The game would be easier to parse with some intermediate stages. Start with only cubes and a worker, allow to sell the cubes for coins, then buy a machine with coins and sell the paint for more coins, and so on.
Personally I thought it was kinda fun to figure out what was going on in the factory and how it worked, but simultaneously frustrated because there wasn't much to do for the first minute. Introducing the game in stages instead of everything at once would also solve this issue. Then show the full factory in the main menu so the player can anticipate how much there is to do.
Some direct use for paint as an intermediate resource would be nice, I don't know how though. Maybe spend paint to upgrade the drone later on.
Add a short intro explaining that you're making a cube painting factory, so the player knows painting cubes is the end goal. To add to this, I liked the painted cubes, not so much the cube being slurped up and put into a generic capsule in liquid form. I just had a liquid to paint the cube, why does the cube go back to a liquid? It would be more satisfying if the painted cube gets dropped into a delivery truck for instance. Or even better, in a stockpile where the player can choose to spend the cubes as currency or sell them for coins (more choice, more gameplay).
Adding some particle effects and sounds to the different processes would also do a lot. And personally I'd like to zoom out to see the whole factory. Great prototype so far, I hope this feedback helps and you can find inspiration to add more features.