Self-explanatory title. I'd like a mode that plays similarly to MKM: Sub-Zero, that combines MK gameplay with a little platforming.

You should end up playing as various characters throughout that mode, and even have some segments/puzzles that require a particular character's special moves. There should be no variants for the characters, as they should be able to use all their moves, except in fights against other regular characters (including bosses encountered in the arcade/ladder mode), in which case, you either get to select your character's variant, or the game selects it for you.

It should also be a little like Super Smash Bros: Brawl's Subspace Emissary mode, with more than one playable character during segments, only you should be able to switch characters anytime you want. Said characters should be killable, which, in some levels, should leave you stuck and having to start over.

Once you beat the story mode, you should get to play as any characters you want in any levels, though for the sake of certain segments, specific characters would be authomatically picked alongside those of your choice. Cutscenes could either stop playing, or remain the same, even if you selected characters that aren't a part of them. Beating that mode should also unlock a Boss Rush mode, but unlike SSB: Brawl's Boss Battle mode, you don't get to heal your character after a fight if you're playing it on the hardest difficulty setting.

All bosses should be designed to be defeatable by everyone, but certain characters should have a much easier time defeating certain bosses.

Finally, some ideas for chapters/levels: Kotal Kahn's rise to power, as he fights a variety of characters and creatures like Shokan and Centaurs with the help of some playable loyal henchmen/women (like Kano for instance), and another where Torr is above you and throwing obstacles your way.