Please, for the love all that is sweet and sugary, just use size one font and separate the categories properly. I actually had to put this in a quote window to get a proper overview, and that's just plain annoying. I'd also strongly recommend listing the cards in alphabetical order with clear quantities for each type of card. And for goodness' sake spell the card names right; if this is the state of your actual decklist I'd strongly suggest writing out a neater copy. There's no mistake quite as pointless as incurring a penalty before you even sit down at the table, which will happen if your decklist is messed up. :\ Besides, clean formatting adds a lot of reader convenience and makes people feel more inclined to give you a rate. Just format like so:
Monsters (20)
3x Dekochi the battle locomotive
3x Emissary of the afterlife
1x Exodia the forbidden One
1x Left Arm of the Forbidden One
1x Left Leg of the Forbidden One
1x Marshmallon
3x Mystic tomato
1x Neo Spacian Grand Mole
1x Phantom of chaos
1x Right Arm of the Forbidden One
1x Right Leg of the Forbidden One
1x Sangan
1x Spear cretin
1x Spirit reaper
Spells (10)
1x Card trader
1x Dark factory of mass production
1x Heavy Storm
1x Level Limit - Area B
1x Monster reborn
1x Pot of avarice
1x Premature burial
1x Scapegoat
1x Swords of revealing light
1x The shallow grave
Traps (10)
1x Draining Shield
1x Gravity bind
1x Magic cylinder
1x Negate attack
1x Ordeal of the traveler
2x Sakuretsu Armor
1x Spirit barrier
2x Trap hole
Side Deck (15)
1x Cloak and Dagger
1x Damage condenser
1x Double Snare
1x Final Countdown
1x Gear Golem the Moving Fortress
1x Karma Cut
1x Magical mallet
1x Monster recovery
1x Negate Attack
1x Physical double
1x Sakuretsu armor
1x Soul Reversal
1x Stealth Bird
1x The Shallow Grave
1x Wave-Motion Cannon
Didn't Icha already sum up the problems with this deck before? It's still all over the place with cards that have absolutely no relevance for what should be your main goal: searching out Exodia. This is a format where OTKOs and even FTKOs are absolutely rampant, so if you think playing flip-flop with Dekoichi (or spear cretin x.o) is going to get you anywhere you're sorely mistaken. *Sigh* Again, the best fix that can be offered here is scrap it and rebuild. All of the top-tier decks (heck, even quaint variations like Rainbow Dark OTKO) are just way faster at reaching their win conditions than this deck is. You really want to get Exodia on turn one if at all possible. I'd recommend either taking a leaf out of Ohm OTKO's book (because that build, it has been proven in an actual championship duel, can cycle through the entire deck on an opening turn) or using the Cyber Valley/Dimension Fusion loop, which also lets you draw your entire deck in one turn.
Optionally, you could try integrating exodia into a standard dark return deck, focusing on dump and recursion while hoping that the countless bad draws those limbs will give you won't kill you or you could even try something bizarre like Demise Exodia (using Advanced Ritual Art to drop the Exodia pieces into your graveyard. Good luck doing that with limited Advanced Ritual Art, though. :\).
All I can say is take a look at the decklists of the few semi-successful Exodia players from this year's Shonen Jump tournaments to get a picture of the kind of draw power you need to be successful nowadays. (and keep in mind; even those strategies were too inconsistent in the end)
Okay...let's at least cut the cards that just need to go, by category to give you a bit of a 'why' here:
The irrelevant
Main (-8)
-1 Magical Cylinder
-1 Neo Spacian Grand Mole
-1 Phantom of Chaos
-2 Sakuretsu Armor
-1 Spirit Barrier
-2 Trap Hole
Side (-10)
-1 Cloak and Dagger
-1 Damage Condenser
-1 Double Snare
-1 Final Countdown
-1 Karma Cut
-1 Monster Recovery
-1 Physical Double
-1 Sakuretsu Armor
-1 Stealth Bird
-1 Wave-Motion Cannon
I seriously have to wonder what you were thinking when you included these. Remember, the point here is to assemble Exodia, and none of these cards are helping that goal. One-for-one tradeoff cards like Sakuretsu and Trap Hole are good for creating openings for your attacks, as is demonstrated by gadget, but Exodia is not really interested in attacking at all because you're looking to declare instant victory; your interest in life points should only go to the point of making sure that you always have at least one left. Battle damage, on the other hand, is something that you might as well forget about, because there's no way a monster lineup this puny is going to smash face. Grand Mole serves exactly the same purpose with its bounce effect, and thus should be cut for the same reason. And speaking of puny monsters...those just about defeat the point of using Phantom of Chaos. The Phantom is a good card, yes, but only for decks that teem with big monsters like Plasma, Dark Armed, Darklord Zerato, and the like; your deck just really has nothing the phantom would like to remove. Karma Cut is single monster removal (and an expensive form at that) and thus also needs to go, and the same can also be said for Cloak and Dagger. Magic Cylinder and Draining Shield are, again, cards of interest only if you want to manipulate life points, which, again, isn't the point with Exodia. Spirit Barrier is really no good for anything that doesn't run Cloudians, Final Countdown is no good for a format where FTKO and OTKO rule supreme (and even if the format were slower, that's a card you need to wrap your whole deck around) and I honestly don't know what possessed you to even consider Double Snare or Physical Double. o.O Damage Condenser really has no useful targets either.
The slow
Main (-12)
-1 Card Trader
-3 Dekoichi the Battlechanted Locomotive
-3 Emissary of the Afterlife
-1 Gear Golem the Moving Fortress
-3 Mystic Tomato
-1 Spear Cretin
-1 Pot of Avarice
Side (-3)
-1 Soul Reversal
-1 Stealth Bird
-1 The Shallow Grave
Like I've already stressed multiple times: this format is blazing fast with a lot of big monsters getting summoned in a scarily consistent manner, typically backed by spells of mass destruction. As such, waiting for your opponent to kill your monster by battle will most likely fail because you will be wiped out on the turn that happens. (Dark Magician of Chaos is also all over the place, and he makes Tomato and Emissary cry over their lost effects like few other cards can) Dekoichi's 'draw 1' effect is also far from stellar, especially since you have to set it before getting your card and with the current dumping going on, Spear Cretin is liable to put something big and nasty on your opponent's field. Again, it's not worth it. I'm going to be suggesting something far more brutal in the way of draw mechanics to replace these, don't you worry. Also, most of the stuff that gets special summoned in painful loop is size Jinzo and up, regarding Gear Golem as little more than a nuisance.
The metagamishly disfavored
Main (-1)
-1 Gravity Bind
-1 Level Limit - Area B
-1 Ordeal of the Traveler
-1 Swords of Revealing Light
Side (-1)
-1 Negate Attack
Yes, I just suggested that you give the axe to three dead standard stall cards. I know this may seem counter-intuitive, but with Dark Armed around these just aren't what they used to be. Cards on the field don't have long to live, so the continuous protection effects really won't help much as they will be disabled for that one, fatal turn when five, 2000+ Atk dark beatsticks trample you. Reactionary traps like Negate Attack are also far from stellar because the current top decks all happily blow them away in the main phase before they get a chance to activate. Negate Attack really doesn't have a place outside of counter fairy, anyway, because you've got both Threatening Roar and Waboku in the way of protection traps, both of which are chainable to the effects that would destroy them and thus superior choices.
Which leaves us with...
Monsters (8)
1x Exodia the forbidden One
1x Left Arm of the Forbidden One
1x Left Leg of the Forbidden One
1x Marshmallon
1x Right Arm of the Forbidden One
1x Right Leg of the Forbidden One
1x Sangan
1x Spirit reaper
Spells (5)
1x Dark factory of mass production
1x Heavy Storm
1x Monster reborn
1x Premature burial
1x Scapegoat
Traps (0)
Side Deck (1)
1x Magical Mallet
So yeah, not much of the original deck left. Buuut...this will soon be remedied, using some of the more modern deck cycling tools around. Basically, I'm looking to make this deck less dependent on your opponent's actions (heck, my primary aim here is to make this a pure solitaire deal. xD), and to do so we need cards that let us draw other cards without passing the turn to the opposition in the mean time.
Monsters (18)
2x Broww, Huntsman of Dark World
3x Cyber Valley
1x Dark Magician of Chaos
1x Exodia the forbidden One
1x Left Arm of the Forbidden One
1x Left Leg of the Forbidden One
1x Marshmallon
1x Right Arm of the Forbidden One
1x Right Leg of the Forbidden One
1x Royal Magical Library
1x Spirit reaper
1x Toon Cannon Soldier
3x Thunder Dragon
Spells (22)
3x Allure of Darkness
1x Card Destruction
1x Dimension Fusion
2x Hand Destruction
1x Heavy Storm
2x Machine Duplication
1x Mystical Space Typhoon
1x Monster reborn
1x Premature burial
3x Spell Economics
3x Toon Table of Contents
3x Upstart Goblin
Traps (0)
Side Deck (15)
2x Appropriate
2x D.D. Crow
2x Dust Tornado
1x Hand Destruction
1x Mind Crush
2x Rainbow Life
1x Royal Magical Library
1x The Transmigration Prophecy
3x Threatening Roar/Waboku
So yeah, basically the aim here is to draw into the game-ending combo of Cyber Valley, Machine Duplication, Spell Economics, and Dimension Fusion. Once you've got those four, all you have to do is duplicate valley, then create an endless loop by using Valley's draw two effect (removing two of them), then Dimension Fusion, then using the third valley's graveyard recursion effect to put Fusion back at the top of your deck, followed by using the draw two effect. Just lather, rinse and repeat until you hit Exodia. In the event that part of Exodia would be removed, this one also comes with an alternative infinite loop using Toon Cannon Soldier to toss Dark Magician of Chaos for 500, followed by Economics-backed Dimension Fusions (which are always recurred by the magician's effect) until you drop your opponent's life points to zero. The rest is just aimed at drawing into and deploying these cards as consistently as possible.
Anyway, I don't have the chance to test this build myself, so I can't guarantee the results (nor do I know what cards you have available), but I can, however, be quite secure in saying that it's better at what it does than the original. There are many ways to go about Exodia, though, so I'd suggest experimenting with the new and trendy draw cards until you find the deck that best suits your play style. I especially stress doing this with your side deck, as you may want to put in something that gives you an edge against the local crowd.
Regardless, I think the best piece of advice I can give you for the tournament is to just relax and have fun with it, win or lose. Getting all stressed and worked up over it will just tire you and weaken your gameplay, leading to the most ridiculous and pointless mistakes (oh, the idiotic plays I've made on my tired, late-night sessions with the DS xD), but even worse; it will defeat the point of playing the game in the first place. Children's card games are, after all, meant to be enjoyable as well. ^^
