I used Klas Kroon lessons on building oldschool tile-based games to try to build a kind of mario-like game engine. I created all graphics, and added several features :
- A level editor, to create new maps and save them in a database, edit the existing maps or delete them.
- A shop system, for a kind of RPG-like feeling : you can buy an sell useful or just collectible items.
- A save/load function, to register your position in the game.
You can take a look here to see how it moves (this is not a final version).