This deck is designed to drain your opponent's LifePoints while holding them back with silly little spells and traps.
Basically, the card "Bad Reaction to Shimochi" makes it so that each time your opponent were to gain LifePoints, it would be negated, and they would instead LOSE that same amount of LifePoints. Combo this with the card "Gift Card" which gives your opponents 3,000 LP. So just by activating 2 "Gift Card"s while "Bad Reaction to Shimochi" is on the field can kill and opponent. This also combos with "Dark Cure", as each time your opponent would summon a monster, they gain LP equal to half of its ATK. So just by playing the game, they're losing.
Next, you'll want to activate your "Dark Room of Nightmare" card. This will make it so that each time your opponent would take damage from a card effect, they take 300 more points of damage. This stacks with every single damage-dealing effect in this deck. This includes "Mask of Despell", which equips to an opponents' spell card, and each time their turn starts while that card is in play, they take 500 damage.
There is a card called "Coffin Seller", which deals 300 points of damage each time a monster is sent to their graveyard. This stacks with "Dark Room of Nightmare", making that damage 600.
To sum it all up, this deck is built to stall your opponent and force them to take thousands of damage just for having a turn. If you have any recommendations, let me know in the comments.