Lol I used Pit and flew from each side of the stage with normal jumps, and his Up B just grab the edge everytime, youll get hit but nothing that isnt manageable, also kill alloys until only two are running around, it seems like the game only resets 5 alloys after there is only 1 remaining on the field, so if u keep 2 alive no more will spawn, ive seen it happen mostly with yellow and blue alloys but some other combos have worked, occasionally a bo-bomb will kill the two and youll have to either deal with 5, or kill down to two again. Good Luck.