This guide teaches you how to easily and reliably get a x50 Combo, plain and simple.
Go to Juggle
On the Main Menu, go to the Juggle gamemode:
This is where we'll be getting the achievement.
You don't need any special characters or special abilities, but I recommend trying this with some unlocked weapons cause some might make this easier.
Now to the Achievement
Now that you're in, you need to get close and do a Strong Upwards attack (S + 🠝 on keyboard)
Now you need to time the same attack again to hit him as he hits the ground. A good rule of thumb is to time when to hold down 🠝 + 🠞 and when to press S.
You want to always be next to where he lands to make sure you don't miss him, but get too close and you might end up pushing him, this is why its important to find out when to hold down the directional buttons to move near him, try to time this whole "combo" to when he's about to hit the ground.
Depending on which weapon you're using, the timing may vary, but do this enough and you'll get the timing of your weapon right.
I've used Creed to do this achievement, but I recommend Longpale, I did not try with all weapons so there might be one that makes this stupid easy.
Do this 50 times and good to go!