2014-09-20 : If some of the creatures are illegal targets as Incremental Growth tries to resolve, the remaining legal targets still get the appropriate number of +1/+1 counters. If all targets are illegal, Incremental Growth doesn’t resolve.

2014-09-20 : You must choose three different targets in order to cast Incremental Growth. You decide how many +1/+1 counters each creature will get as part of casting the spell.