well that movement is pretty serious IMO. Are you able to turn the engine over by hand?
If so check the top of the block and see if the pistons extend above the block.
If it does, it's gonna need some parts, maybe everything in the bottom end?
I'd pull a cap off a couple rods and see how the bearings look. Might pull a crank cap and check the bearings by that piston you show in the video.
But personally i would not run it that way, or spend to much money on it, with out investigating further