Use the lower level monsters and keep destroying keith's monsters. Don't attack if he has a face-down trap since it could be rare-metalmoprh. Set a magnetic mosquito if you think he will tribute summon either blowback or barrel dragon. Use acid raid if you don't have mosquito to destroy his tribute monsters. It's best to summon BEUD during second to last turn to avoid it getting destroyed early. On the last turn, summon vassal and use the union attack combo.
Summon either the hunter or jerry and destroy keith's monsters when they are in defense position to not lower his LP. If they are summoned in attack position, switch it to defense using otohime on the next turn. Acid raid if their attack is higher than yours, or mirror wall to defend as well as reducing your LP. Lower your LP to more than half of keith's LP and keep destroying his monsters so the BEUD can get a direct attack to deal 10,000 damage after equipped with sword of deep-seated.
Since the ATK of Twin-Barrel Dragon is 1700 and same to that of Axe Raider, the highest ATK level 4 monster you can get, you need to use equips spells or other ATK boost cards to get your monsters to defeat the dragon.
Use Spell/Trap removals
Destroying Keith's Machine Conversion Factory, Second Coin Toss, and Rare Metalmorph is important to help your monsters to beat Keith's Machine monsters.
The other anon said that Labyrinth Deck work well too. So, this is my ver.
Only use Dim Gate when the Wall is target by the Coin Dragon.
If 1 or 2 of Dragon is on the field, consider to use Acid Rain. That spell is to get rid the dragon only, dont waste it on other monster.
Y fusion gate? To avoid your hand full with cards so you can set it face-down on the field spell zone. If you get ur fusion monster earlier (I use Oz), summon it immediately and set a Dim Gate. Try to clear the Dragons. And if target by them, just banish it with the Gate.
Y monster draw power instead of spell/trap? To avoid the dragon target your gate. You need just 1 or 2 draw monsters to draw last card in ur deck b4 Bandit.
At the last turn:
1) Pop ur Storm, destroy 2 Dim Gate and 1 Fusion Gate (make sure u have fusion ur monster first), clear the backrow.
2) SS the wall in ATK position
3) Use Shield & Sword
4) Summon Vassal -> Secret Pass -> Union Atk
DO NOT USE the Mystical Union Deck
as it is shown above...
you and your monsters never survive long enough to tribute-summon MysticalBeast cause no matter what you place... if not by then he placed his SecondCoinToss and your screwed anyway... the only way to "farm" with this deck is with a "perfect" hand/field on the second last turn... THIS DECK IS PURE LUCK
use this deck
and try to build your own variant
if you only have 1 DimensionGate like i do... but some MegneticMosquito or equal monster cards i guess you can banish your LabyrinthWall in your turn with DinensionHole and place a monster just to protect your Wall... its a guessing game but might can help for a cheaper variant
Your deck is nice bro. But i think you have to change the draw power trap card to any monster that draw card. Cuz your spell/trap zone might clog up with dimension gate and you need 8 cards in the last turn! (1x double summon, 2x union, 1x temple king, 1x secret pass, 1x serket, 1x vassal, 1x axe) WOW that's so many to hold!
Lab deck's weakness is too many cards in your hand before reach the last turn but cannot set some of them in the spell/trap zone. So replace any spell/trap draw power with monster draw power like skelengel or the train.
Fuck this cheating ass cunt of a bitch with his coin bullshit nobody likes coin bullshit fuck him and his dam as robots he can rust and rot in a fucking grave for are I care with his cheap cheating self,cheats in the show cheats on this dam game so fuck this cheater
.AND KOMANI MAKE THE DROP RATE BETTER FUCK I DO NOT WHAT TO FARM THESE BITCH ASS DUELIST WHERE IT TAKES A FUCKING LIKE A YEAR TO GET THE DAM CARDS I WANT BULLSHIT JUST FUCKING BULLSHIT DUMBASSES.
This deck is almost the same as one above. Never let him have one monster for a tribute for his annoying 6* monster. If you planning to get only effect damage remove his monsters with acid rain and cards like 4 star ladybug and mosquito. Also do not attack his monsters which have similar atk than your monster because he can use rare metalmorph. Hunter can be exchanged for any 1750+ atk monster.