I went looking to try and find my own answer.

Logging in to be a developer on B&N, Amazon and Google I found similar information. You need to download Java Development Kit and Android SDK. Also you need an emulator of either Kindle or Nook etc. A debug Bridge (ADB). Plus other stuff!

Also I saw mentioned on both Amazon & B&N about DRM.
So it seems all these place use java programing, with the android OS to make their apps. Each site adds programing language to let the 'games' work with their ereaders. Also DRM can be added if the developer wants.
So I think ~ AnemicOak has the best answer for me. Getting something like a Nexus would be the best for just playing games because of the large supply available.
Now if what I thought I read is not true enough, please feel free to correct me.