2014-09-20 : The enters-the-battlefield ability can target Armament Corps itself.

2014-09-20 : You choose how the counters will be distributed as you put the ability on the stack. Notably, if you choose to put one +1/+1 counter on each of two target creatures, and one of those creatures becomes an illegal target in response, the +1/+1 counter that would’ve gone on that creature is lost. It can’t be put on the remaining legal target.