KillerJawz: Luigi's airgame is far better then ours, I'll come out with it now. Equipped with fair, he can chop through our spam and give us a real damage racking by forcing us offstage or just getting into our area. When Luigi is in, get him out ASAP, otherwise, he will have a variety of chains on you, and since Samus is tall and floaty, his uair and utilt strings are BEASTLY. Luigi's nair, dair and bair attacks can all clank with charge shot so it just goes past him rather then damaging him, so please just try and hit him while he's grounded. If Luigi doesnt powershield this, he is being sent back about the third of FD's length, so yeah, keep that pressure on. Luigi's dair has a very small spike hitbox on it that is pretty weak but can catch you off guard, and even if the spike doesn't kill, it can set Luigi up to gimp you.
Luigi has the ability to gimp Samus. Whilst its very very difficult, it's possible and can be quite frustrating. Basically, Luigi's rising down B tornado has a sort of pull when it connects with you, if you are bomb jumping, this move will pull you out of your jump and throw you somewhere off stage, where Luigi will be able to edgeguard you, be very very careful when bomb stalling, never do it when Luigi is below you. Either go for a spike on him or gimp him with missles and zair, since these stop down b's momentum dead in it's tracks.
Luigi's jab can be cancelled into a variety of moves, including his Up B which is a MONSTER of a killing move and will end us around 75, so please be careful, also note that if we are slightly airborne when he jabs, we cannot avoid it, and are simply going to eat an Up B. If you are at lower percentages he will follow up with pivot grabs, more jabs or even tilts/smashes. On this point, Luigi's ground game just destroys us outside of our ftilt, it outranges all of his moves, but it's still quite nasty to get hit by one of his ground moves, because literally all of them combo into another move, even his freaking down tilt :/ (Up B can be done out of his down tilt if it trips you)
A word of warning, DO NOT FOLLOW UP A DTHROW WITH A CLOSE RANGE AERIAL. Luigi has a move which I have nicknamed "Carrier" which is his neutral aerial. This move is a very very strong kill move, especially when it's used as a rising move OoS, it's extremely destructive and is quite difficult to DI. It works extremely well on floaties like Samus and is very dangerous, so look out.