User blog comment:KirbiMiroir/Clones 4 CA$H/@comment-26394058-20160222035243/@comment-12498802-20160222073927

Here we go!

For starters, Lucas' Standard Special shoots a snowflake that explodes on impact, slowing enemies in the blast radius. On the other hand, Ness' Standard Special shoots a ball of green energy into the air. You can control the ball fully once it reaches the peak of its ascent.

Lucas' Up Special lands lots of little hits, whilst Ness' Up Special lands one big hit. For their Side Specials, it's the other way around! Finally, Lucas can heal himself more efficiently if he absorbs a projectile with his Down Special, but unlike Ness, the magnet doesn't guard his back.

Finally, Lucas' Final Smash has diagonal knockback whilst Ness' Final Smash has vertical knockback. In addition, Lucas isn't in Smash 4 unless you have the necessary DLC.