Im not the best programmer, and my knowledge of blueprints isnt the best. But, from that rotation variable/node can you drag a node and chose “break vector”? That SHOULD break the rotation into x,y,z coordinates. If you could upload your file that would be amazing, because then i could just try to work out a solution for myself. And i imagine if you want to do the mouse thing that you would just have to limit the mouse to X and Z so it can never move back or forward.( which i assume is what is done with the character if its a side scrolle r) Im not 100% positive how to do this exactly. Sorry im not much of a help, just throwing ideas out there for you to try.