Level 2 (with its body intact and it has 3 head things) - Go to either side of his head and attack, all his attacks will miss and you can only be harmed by his spinny thingys (sorry dont know name)

Level 4 (last one, fires grants) - when it shoots them ball like things run until he shoots the last one and let the last one hit you,
you will be damaged but you should miss grants (80% chance of missing)

Here is a more suitable translation and additional details for all phases.

At Falz Teleporter:
Chain your Pbs to get the highest level of S / D you can get. If you do not have 100 by then, boost the chain by pressing the end button.
Or the Emoticon button once it activates.(Make sure your mag's synchro is at 200...) You can achieve a Lv81 S / D by doing so.
Also, Jellen doesn't affect Falz in any ways.

Phase 1:
If you are invincible when you transport to the memorial, immediately run up to activate the phase, as you can have a short period of time when you are invincible to avoid the darvants that come in. Use gifoei if you are a Fo (Heal when someone takes damage, extremely important in Ultimate.), and ranged weaponry as a Hu / Ra (Preferably not Slicer.)

Phase 2:
Go to the sides of each head. If you are a Fo, zalure first, and then stay in the center and spam Rabarta to stop the unwanted Darvants.
Each of the attacking players should attack their own selection of heads, as to avoid damage canceling.
And as usual, heal when applicable.

Phase 3:
All Difficulty:
Fo zalures, then switch to healing. If you are using Fo boost gears, use barta and support. Rest of the team does whatever.

Ultimate:
This is the point where most of the Pso population suffers the most due to Falz' Rabarta. Get a cure / freeze if you can.
Everyone should spread out so you don't take your team out due to clumping. If you are frozen, use the direction keys of a + d to quickly get out before you get killed by the oncoming darvants. Once it is all over, have fun owning his hell of a lot easier last form.

Idola Phase:
All Difficulty:
Fo Zalures, then switch to healing. If you are using Fo boost gears, use foei and support. Rest of the team does whatever. As a note, you can do what he said in the original post of the blue bubbles. Do not do this Ult if you don't want to get Ohko'd. Avoid hitting Falz when he takes a
soul since if you kill the player, it will only prolong the fight. You should only let the player who had had his soul taken to hit.

Ultimate:
Attempt to dodge all the bubbles by running Diagonally and not clockwise / counterclockwise. If you do get hit, it will only damage you and not kill you. (Unless your Hp is very low.)

Edited to fix awesome typos.

now i know how to beat him! Huzzah - Thanks guys :]?

Not all that relevant but they're called Darvants and this- ahem these strategies are nice I'll have to try em out