Tank! Tank! Tank! is the poster boy for this thread. It started life as an arcade game (you know, the type you drop a few quarters on to enjoy for 10 minutes and then move on to something else), but someone had the idea to charge it for the same price as a full retail experience such as Assassins Creed 3 or Darksiders 2.
It's fresh on my mind because it's soon going to be free-to-play, at least for you Europeans. You can find more details here: http://www.nintendolife.com/news/2013/02/nintendo_download_14th_february_2013_europe
I hope us Yanks get the same deal. I'd get the game and a couple of packs for that deal.







