Well, my next improvement will be done on the Insane Tower Builders game. Right now the only game mode is to try to build as high as possible. I thought a puzzle mode would be a nice addition, where the builder would build towards Gold, Silver and Bronze medals scattered in the world.
The puzzles will be defined by xml. The first version will have an embedded .xml file with the puzzles, but the intention is to later have downloadable puzzles stored in shephertz, which is my online service of choice.
An even further advancement would be a system where users could edit their own puzzles in the game, and then upload them to the online storage for others to download, play and rate.
A puzzle definition will contain the points, the static tile placements and the list of tiles available to the user.