You can always buy codes in smaller amounts through this link
The games central concept is simple enough: you are a powerful wizard dueling against other wizards, and every card represents a spell you can cast
There are no timing restrictions to boast other than it has to happen after attacking with that creature, and it can only happen once per turn
The entire deck is based around turning land drops into noncombat damage, and Valakut Exploration is just another way to do that
The recurring value-oriented nature of Sun Titan targets lend themselves naturally to Restoration Angel-based strategies, such as Yuuya Watanabes U/W Control deck from Worlds 2015: Creatures (16) Lands (26) Spells (18) While Dragonlord Ojutai is sturdier, Sun Titan can be invaluable for going over the top of opponents, for actually ensuring hes got enough advantage to close it out
Ive honestly been giving some thought to Sphinx of the Steel Wind in this slot instead, but Blightsteel Colossus being able to win the game in one hit is better if you want to go that route