When I recently asked about the uses of Ruby someone told me it was good for prototyping. I basically know what that means, quickly get the very base of your app up and working, see if there are conceptual problems and then add the rest.
Yep, prototyping serves as a proof of concept, to ensure what you want to build is feasible. Something might be left out in a prototype could be like exception handling, logging, etc.
A common mistake often made is teams switching from prototype to real code on the fly, i.e. just continuing on the so-called "prototype", except it just now becomes real code.
Yes, that's a good basic description of prototyping. It's just getting the foundations working so that you know it can be done, and that it suits your needs.
An example of a Snake game prototype would be having a snake that you can move up down, left and right, eats something, maybe have one block in the middle of the board to maneuver around, and the snake growing when it eats something. So, you wouldn't have a splash screen, or keep track of high scores, or have different levels. Just the basics of the game.
For many clients, describing what an application will do, or enumerating a set of requirements, is not enough for them to fully grasp how it will work. This leads to the infamous mid-project changes and scope creep. One way to mitigate this is to create a throwaway version that lets them see a "working" example of how the real application will operate.
It can often function as a proof-of-concept as well, but I think client communication is the more useful purpose of a prototype. In particular, you may want to do a prototype using a different technology -- Ruby/Rails, say, or pure Javascript -- than the final working application will use. If so, there's still proof-of-concept value in terms of the algorithms you're using, or the ways you may have to connect to other systems, but again, the actual code will all be thrown away.
So the part of your description I would disagree with is "add the rest" -- I'd throw the prototype out and start over.
Is "Good for prototyping" a polite way of saying "It's difficult to maintain"?