As awesome as this deck is, I would make a few changes to it before fielding it in a multiplayer setting. While playing 24 lands and 36 global burn spells (figuratively speaking) seems like it would be badass, the reality is that you probably won't be winning many games. Most of your cards hit players and deal with small creatures, but a 4/4 is going to give you some grief. If you take even 1 swing from something with 3+ power, you'll probably die before any of the other players. You better ****ing believe that you'll die in a blaze of glory, but still, you won't win. I love mass burn decks because they make for fast games, don't get me wrong, but I feel like most people are missing one key element: defense.
If I had to write a Red mage bible for multiplayer, it would probably start and end with
Glacial Chasm 
. It's without a doubt the single best investment any Red mage could possibly make for multiplayer. When you play this card, you will win the game. It's that simple.
To reinterate, what your list lacks, as with most lists, is a way to actually protect yourself while you're burning everything down. When I build red burn decks, I start with something like 4x
Ensnaring Bridge 
or 4x
Glacial Chasm and build from there. My top priority is always going to be survival above all else, because you can't win if you've already lost. Speaking of which,
Warrior's Oath 
has the best reminder text ever! Red mages, you don't lose if you've already won!
So, with that being said, my advice would be to worry more about survival and less about what 36 burn spells you use. I mean we could debate
Earthquake 
over
Fault Line 
and other trivival changes for eternity, but at the end of the day your burn spells don't really matter. What matters is your plan to survive long enough to cast them. Again, I would pick
Glacial Chasm over every other card in the game, but that's me.
Sun Droplet 
can work too, but honestly, it's not nearly as good.
On a separate note, if I had to make general comments about Red decks, cards like
War Elemental 
and
Taurean Mauler 
are always good. The Elemental loves your global burn, and the Mauler is just a solid defender/beater. I also hate Planeswalkers in multiplayer (in general) because all they seem to do is draw hate and die. Neither Chandra has a particularly strong first or second ability, and so you're playing them for ultimates that you shouldn't be seeing. They're cool but not very good sadly. Finally Red decks also SUCK ASS at drawing cards.
Mind's Eye 
is so freaking expensive, and
Browbeat 
isn't reliable. Still, it might good in this deck since life totals should be low. Maybe consider adding some of those? It's that or
Howling Mine 
/
Temple Bell 
effects which also have drawbacks... big ones at that.
Grafted Skullcap 
is good with
Ensnaring Bridge , I should point that combo out while I'm at it.
spells. Yes, you can win easily with the cards you have. But they're not going to work every time, and your opponents will have gorillas on the other side of the board. An X spell gives you the ability to take them out, as well as giving you an extra win-con. I'd go for 
Elves)
