Super Mario Bros. Dimensions (Demo 3)
Super Mario Bros. Dimensions is a fangame made using DragezeeY Engine VII. It features 8-bit graphics, mostly taken from SMB3. What sets it apart is that the player has the ability to switch between two different "dimensions" of a level, which changes the level's layout and appearance. It will also allow you to tackle its worlds in any order (except the first and final worlds), and you will be able to save records for time taken and coins collected in a level.
The full game still isn't ready for release yet, so you'll have to settle for the latest demo, which was released earlier this year in August. Please understand. However this version does contain a few further bugfixes.