Yes, there is hope for a high-level heuristic understanding. Here's my attempt to explain in more familiar terms.

They train a new neural network from scratch for each problem. The network is trained only on the data about that problem. The loss function tries to make sure it can map the inputs to the outputs. It also tries to keep the network weights small so that the neural network is as simple as possible. Hopefully a simple function that maps the sample inputs to the sample outputs will also do the right thing on the test input. It works 20~30% of the time.