It does have an emphasis on creature-centric decks, but most green builds--including enchantments and especially modified--will have no shortage of creatures on the field
However, if you do choose a target, and that card is an illegal target as the ability tries to resolve, the ability won't resolve and none of its effects will happen
The other big issue for this guy is that he is all rather back loaded
It seems to me that he would prefer to bide his time, sculpting your graveyard for the perfect moment to unleash the might of your deck on your opponents
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
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