Thanks, I was wondering about that because the last time I did it, when I held the jump button longer I don't fall to super fast, let's say I just get more air with marth when I jump, and then spike, but either way I guess it's good, if I'm wrong please correct me.
One last thing though, do you fall after the person when you can spike that person?, or is that just asking for trouble? When your also falling to your death?
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I'm not sure what you are asking, but I'll say somet some general stuff you might have missed.
When you use the C-stick for spiking, pressing down on the C-stick will also make you fastfall. So, in order to make sure you don't suicide yourself, what you do is you jump, and then BEFORE the peak of the jump, you press the C-stick down. If you press the C-stick at the peak, it will cause you to fastfall.
I'm not sure about what the person said earlier (sorry forgot the name) about tapping lightly on the control stick, since I almost always use C-stick. But even if that is true, you still want to Dair before the peak of the jump, or else you could lose too much height and could get edgeguarded if you miss the spike, or just fall to your doom.
@Revox
Yay for you using Marth :D
No, counter does not counter Final Smashes (well, at least not most of them). Counter does counter any attack though, including melee, projectiles, or even something like the wind from King DDD's Neutral B (the Inhale attack).
Um there really isn't any of way except for dodging the grenades and/or shielding, sorry. And you shouldn't have to shield that much, throwing a grenade takes a lot of time. If you run, you should be able to reach him in 1-2 shields (assuming if you're running on the ground and don't jump).