Hey thanks for playing the game. All the mechanics in the game are near identical to Melee, including the 2 jump heights, the walk and dash difference and importantly the lack of an input buffer. This design is quite unforgiving and has a steep learning curve, but I do think it is very rewarding when mastered.
It's tricky because I think smash gets away with this more because for a beginner the chaos of it all is the fun. Plus since the mechanics were designed with fighting in mind, there are numerous restrictions to give risk to movement which is important for the fighting design. It's only when you master the movements and employ exploits like wavedashing that movement really opens up.
Since this demo release, I've already made a lot of changes to improve the game feel, and I'm always learning what does and doesn't work. But I don't think I will stray too far from Melee's design because I do think there is value in its initial perceived stiffness to its fully realised mastered fluidity. I know a lot of people agree with this too, but it's just a bit niche (unfortunately for my wallet)
As the the xbox controls, ye thats my b. I was trying to mimic gamecube layout (this is what I use), but that was not the right call for the default controls. Also remapping changing menu inputs is stupid I agree, sorry about that.