Placement, Timing, and Your Opponent's %
I played on wifi over the weekend and KO'd a friend using Zelda at around 60-70% (freeze frame lag ftw lolol) with the Knee. Memory might fail me atm, but If it's not because of Zelda's pain animation, then the sweet spot might actually be a little bit OFF of the actual knee graphic. If that's true, it might only work if there's no overlap with the 'weak knee' hitbox.
Someone with a knee screenshot should like... draw a box showing the 'perfect placement' for the knee (Falcon, opponent), and where the hitboxes are (or seem to be). Bet it'll help loads of Falcon players.
Every week, it seems I've been picking a different character to try that most people say suck. I went from Lucario (invisible hitbox ftw) to Link (meh, ranging with projectiles isn't my style) to Ganondorf (people just have to learn to block and combo off of Flame Choke and he's a beaaast) to Sonic (is awesome off-stage <3). I'm feeling like this weekend will be my Falcon weekend, so I'm kinda gauging out his suggested weaknesses for now =D
If there's something I picked up from Sonic,
pay attention to your opponent's % when you get a 'successful combo'. (making up these #'s) A setup like d-tilt to knee might work at 40-60% against a medium-weight character but fail against at 80-100% or 0-20%.
http://smashboards.com/showthread.php?t=164331
like.. that, for example. Maybe, just maybe Ulevo's combos
do work, but only at certain %s for middleweight characters, who knows? If you can figure it out against a middleweight like Marth, you can make adjustments to get them to work against any other character :]
good luck lol