All 5 sprues are identical. Each sprue has everything you need to make four soldiers.
The trumpeter is blowing the charge on a straight tuba (or it could be the shorter salpinx) and is one piece. The Centurion is charging with his gladius ready to thrust into the face of an enemy. He comes with a separate shield. The Signifer comes with a choice of two standards; a signa and a imago (bust of the Emperor). The Optio is a big Celt with long moustaches and a braid. He has a separate shield and his spear arm is separate as well to allow for the more animated gesturing as he encourages his troops to get stuck in.
Assembling the troops too a bit longer than the artillery. There is not as much option for the builds either. The arms go with particular torsos, which I found fairly logical and figured out by matching the flat surfaces for joining, but when I was onto my third sprue I noticed on the back each torso was numbered and the arms also had corresponding numbers. (You can just make these numbers out on the Back View above, located on the sprue stems near the pieces.) Because of the construction of the mail sleeves there isn't as much scope for varying the pose without getting into cutting and green stuff. One figure is thrusting with his gladius, another is thrusting with his hasta, a third is throwing overhand and the fourth has his hasta tucked under arm for some more forceful poking. There are five heads to choose from though, giving some variety. Care must be taken when gluing the hasta in the hands to give room for figures behind to rank up.
This unit is definitely attacking though! No standing about with their spears up for these fellows.
Definitely a worthwhile purchase for any aspiring legate.