Upgrade Games
People sure like upgrading things in games...whether they be about shooting something out of a cannon or shooting cannons at something...or something. Upgrades give some sort of addictive value to games as they make you want to keep playing and playing so you can keep getting better without actually developing any sort of actual new talent. These are pretty much games that continously say you suck and go easier on you each time until you can finally get it right after 200 tries. Fun.
