When I used to play tyranids way back when, I found that a lot of times things would be missing. Usually only a part or two so I wasn't all that worried as I mostly just played my bro at the time and the WYSIWYG wasn't too big of a deal cause the points are really what's representative of the model's worth, not what's actually on the model.
"There is a cancer eating at the Imperium. With each decade it advances deeper, leaving drained, dead worlds in its wake. This horror, this abomination, has though and purpose which functions on an unimaginable, galactic scale and all we can do is try to stop the swarms of bio-engineered monsters it unleashes upon us by instinct. We have given the horror a name to salve our fears; we call it the Tyranid race, but if it is aware of us at all, it must know us only as Prey."