Mari0 (2012) is a fan-made crossover between Super Mario Bros. and Portal. You're Mario, and you have a portal gun. You can play through the classic levels from the original NES game (but with portals!), try and solve the Aperture Science-themed puzzles based on Portal and Portal 2, or even make your own levels. There's a Co-Op Multiplayer mode too—up to four players can play simultaneously, much like in New Super Mario Bros. Wii.
The game is available as a free download at its homepage on Stabyourself.net. An updated version known as the Special Edition was in the works, but due to years of Development Hell, it was cancelled with only a public beta in 2014 ever being released. In early 2018, development of a sequel based on Super Mario Bros. 3 was streamed on Twitch, but with little news since then, don't hold your breath.
This game contains examples of:
- Ascended Glitch: The exit pipe the brings the player to the flagpole in 1-2 has an intentional non-solid tile in the upper left of the vertical pipe, in which the player can portal themselves up to it while big, slide through, and go down the first pipe in the Warp Zonenote to enter the Minus World. The player can also use the editor to clear a wall through the exit pipe and get to the Minus World easier.
- Camera Screw: In the co-op mode, the screen used to scroll to accommodate the foremost player. Anyone else who fell too far behind got screwed unless the foremost player went back, or unless the player who fell behind managed to catch up with portals. SE would've added a splitscreen to fix this.
- Co-Op Multiplayer: 4-player simultaneous, and each player gets his/her own portal gun.
- Crossover: Not just Mario and Portal, but it also has a Minecraft mode and Sonic Rainbooms too.
- Downloadable Content: A handful of mappacks are available, including The Lost Levels. Thankfully you have the Portal Gun this time. Subverted in the 1.6 version since they are actually pre-packaged rather than downloaded (but the menu still lists them as DLC).
- Dungeon Bypass: In addition to the ones present in the original game, the portal gun allows you to creatively get around some obstacles. Use portals for a perfect 5000 flag catch every time, portal behind Bowser to hit the axe, portal Bowser behind you to do the same, and many more.
- Easy Level Trick: Only one player needs to reach the goal to complete the level in a co-op game. This can be used to bypass several companion cube puzzles.
- Game Mod: These appear from time to time on the forums, taking the form of additional map packs and major mods that add more items/enemies/objects to the game. Alesan's Entities is one of the more notable ones.
- Hoist by His Own Petard: Hammer Bros. can be killed by their own hammers sent through portals. Humorously, this used to extend to the hammers of other Hammer Bros. as well; a pair of them often thinned themselves out when the one in back started throwing. This was patched in version 1.4.
- Knockback: An unlockable cheat has Mario ricochet behind himself whenever he shoots with the portal gun. Potential abuse of this can allow players to soar across levels, made much easier if combined with the cheat that allows slowing down time by using the mousewheel.
- Konami Code: Entering it at the title screen unlocks the cheats without having to complete the Super Mario Bros. levels first.
- Medley: The map pack ''SMB Extended'', which combines both Super Mario Bros and The Lost Levels into one mappack. A mod only compatible with 1.6 must be used to run it.
- Nostalgia Level: Up to Eleven.
- Literally the entirety of the original Super Mario Bros. is playable. The entirety of The Lost Levels is also playable, as well as a few other miscellaneous remakes, including ROM hacks.
- Other ports include the PC-88/Sharp X1 pseudo-sequel Super Mario Bros. Special (available here), and another of a ZX Spectrum tech demo.
- A port of the original The Great Giana Sisters is also available.
- Obvious Beta: Downplayed with the open beta of SE, where the only eye-openers are characters having "-unfinished" in their names, and you can't go onto Adhesion/VVVVVV Gel with a mushroom. The level editor also crashes quite a bit now due to all the new features added, and ported 1.6 maps can crash in SE's editor due to missing the "Buzzy Beetle Half" entity.
- Thanks to a rather well-known sprite sheet◊ where most of this game's sprite work was based on, Buzzy Beetles in overworked levels appear to bop up and down as they move, with one of their rows growing an extra pixel in size in one of their frames.
- From the same sprite sheet, we have incorrectly-colored Overworld coins.
- Retraux: 8-bit graphics, obviously, to duplicate the style of the original Super Mario Bros. Averted with the Portal objects and tiles, as they're more detailed.
- The hats available include Rainbow Dash's mane (it's possible to perform the Sonic Rainboom with one of the cheats enabled) and the eponymous striped top hat of The Cat in the Hat. Many hats from Team Fortress 2 are also available.
- The six additional background colors in SE following the standard three (Sky, Water, and Black) are based on the coat colors of the Mane Six.
- "Untitled" Title: "The Untitled Game" mappack.
- Virtual Paper Doll: Mario's sprite is customizable and can be recolored however you like, and you can even give him a variety of silly hats, mostly from Team Fortress 2.