Firstly. Super Mario Bros. X is a executable game done in VisualBasic by SMBX user "Redigit".
It's a game inspired in Super Mario 1, 2, 3 and World. It features 5 playable characters: Mario, Luigi, Toad, Peach and Link, 2 player co-op gameplay, with Split-Screen feature, new unique power-up such as the Billy Gun, a real time level creator/editor with over 1000 objects to use and high costumisation options.
For more information and the download, visit the website.
Super Mario Bros. X Website
Super Mario Bros. X 1.3.0 Download
Super Mario Bros. X Official Fan-Forum
The Star Shards
A Super Mario Bros X Episode
"The Star Shards" is a Super Mario Bros. X Episode done by a SMBX user "Garro". It contains a world and a series of levels like any other episode. This Episode use the Star feature. Where there are 3 Stars hidden in every level. Than later they are needed to continue on the Main Storyline or to get into Secret lands.
Things that this episode offers:
-Relatively short levels but with sideroutes and secrets
-Power-Up upgrade as you advance
-Abusive use of custom graphic and custom NPCs
-The Blue Mushroom Power-Up
-A Time Traveling feature
-Revamped Super Mario World graphics
-Mini-Quest inside levels.
-Secret levels that are optional
-More things yet to be announced.
The project is not complete. But theres a released DEMO you could try for the meanwhile, the download link is at the Download tab.
