how realistic is this game's portrayal of circuit building?
In reality, circuits are built by making a schematic drawing, then laying out the circuit; many different decisions have to be made, and each of those steps takes days or weeks. In addition, you are probably prototyping important parts of the circuit while doing the schematic or layout; these early tests may be with physical hardware or in some simulation software. Spice simulators are more like an IDE than a video game, but they are very limited.
... It's a bit silly that I'm excited at the prospect for properly terrible docs, but it really would add some fun to it. Just imagine if the components have undocumented features, and once in a while you get one that simply doesn't work as advertised. Beat the game? Get certified!