Prowler is a great taster of what the album's going to be like, it's a fast energetic opener which features good songwriting and technical work.
Don't know Killers very well.
Invaders is an average opener for an excellent album.
Where Eagles Dare is too good for an opener, it defeats the purpose of what an opening track is meant to do, it should be in the prime of an album(track 3-6 on a 8/9 track album)
Aces High is perfect for an opener, it gives you a great taste of what's to come, it's short and swift providing the sound of the album.
Caught Somewhere In Time is ok I suppose, nothing special, ideal for the album.
Moonchild is the best, the perfect first part of this concept album-setting the tone for the album. The song has energy, emotion, flavour and generally rocks.