I have just come up with a SP level idea today. I have called it Jazz Under Fire. Sorta like Agent Jackrabbit and 00Jazz. I can't provide screenies yet since I've only just started.
The story involves Devan in a plot to take over the World. It is up to Jazz to stop his evil plan. There will be various missions to complete with some objectives to do before you can complete the mission. Each mission will consist of 4 levels. There will be a Boss every 4 levels. I have just started on the first level. Various tilesets will be used.

BTW, those Owl pics make me laugh.