4) Are there three cards in my opponent's graveyard
Its well built and worth more than its cost (if you can find it for its original price)
If an Adventure spell leaves the stack in any way other than resolving (most likely by being countered or by failing to resolve because its targets have all become illegal), that card won't be exiled and the spell's controller won't be able to play that card from exile later
Most of the creature lineup consists of summons, which are Saga enchantment creatures, with the non-summon creatures being general enchantment and Saga support
Old One Eye Something something big dumb creatures oh wait, Old One Eye is a big dumb creature and creates another big dumb creature when it enters, can buy itself back later in the game, and gives all of your creatures trample
You could just go whole-hog and take an extra turn instead