The goal of an Altergeist Deck is to snowball as quickly as possible; so as to be oppressive as early as possible.
Key cards in successfully employing the oppressive Altergeist strategy include:
• Multifaker: It can bring out Silq for a free bounce, it can bring out Meluseek to set up your next turn (can be used as Link fodder on your next turn or popped during your opponent's turn by the likes of Hexstia or Protocol for a search) / bring out removal, or it can bring out Kunqueary for an impermanence-esque effect.
• Hexstia: It can serve as a trap / spell negate which is significant in this day and age with Striker, Orcust and Salamangreat having powerful spell/trap cards.
• Protocol: It can serve as a negate, and can set up your future turns by activating the floating effects of Hexstia and Meluseek.
With the Altergeist strategy core being discussed, it is important to understand that the best way to play altergeist is to accentuate the strengths of this strategy; the ability to prevent the opponent from making meaningful progress (through a variety of negation, bounce and removal effects). Hand-traps, consistency boosters (draw cards) and traps that can play against the opponent whilst powering multifaker are all good choices. So, without further ado, we'll now discuss the cards that aid this strategy - from this decklist.
• Most of the traps in this lineup either boost the consistency of the altergeist strategy (spoofing, manifestation), are part of the core strategy (protocol) or aid in the oppression. The traps that aid in the oppression that Altergeist is known for are all, for the most part, able to be trap tricked - which helps increase the pace of this deck by giving it immediate answers to an opponent via trap trick. Trap trick, in this deck, can setup Secret Village of the Spellcasters to shut down a Sky Striker player... it can bring out Magic Deflector to shut down a field spell like The Hidden City... it can bring out a heavy storm duster to blow back the mirror match or to prevent any backrow setup by another deck... and lastly it can bring out an impermanence for a monster effect negate.
• The hand traps in this decklist are all there to prevent the opponent from gaining an advantage. Gnomaterial is significant in that it can shut down most T1 decks early on, while Ash & Ogre hit a variety of strategies with the negation / destruction they threaten. D.D. crow in the side & Phantazmay allow the deck to be more versatile going 2nd; potentially hitting GY targets for GY centric decks with D.D. Crow, and potentially seeing more hand traps with Phantazmay.
• Secret Village can be replaced with Necro Valley (just 1 necro valley + 2 secret village is fine too); both of these field spells hit strong meta-strategies incredibly hard.