A MVP is the minimum that a game needs to be to in order to be playable. It doesn't require any graphics to speak of, most items of the game, etc. All it really requires is the essence of the game. Think of a game that you know well. What would be the minimum required to play it? Let's take a few well known games, and see what we can do to break them down.
Having this minimal product will allow me to test out several ideas that are floating in my head before I have a much larger game to contend with. The biggest changes should always be made when the cost to effect them is the least. At this point in time, I've invested about 2 weeks, or about 25 hours of time, and making small changes is quite easy. I can then test out the ideas, see what seems to work best, and keep moving to the best solution for my game. If you want to stay abreast of how the game is coming, feel free to join my Google Group.
The bottom line is, starting with the minimal game, and slowly adding graphics, mechanics, UI, and rules, is the best way to design a game. It allows for maximal flexibility, and is very motivating to have something running quickly. Even major production companies use this approach!
Ben Pearson is the author of the Amateur Radio and other technology blog KD7UIY and developer of Games and Apps at Google Play pearsonartphoto, where he plans to publish some of the games created by inspiration of gamedev.tv. He is currently working on a Sea Trading game, which you can subscribe to updates at his Google Group. He has been a programmer since a young age, although only recently is learning programming with game engines. He has completed the the Complete Unity Developer Course and the Procedural Generation courses, and is working through the Complete Blender Developer Course and Unity Game Physics courses. He is hoping to soon start Unreal Courses soon. Follow him on Twitter @KD7UIY.