The second bit I get, but not the first...

[Richard Hargreaves]

Na, es ließe sich überhaupt allerlei sagen, auch über eigene neue Befehle von oben, die nicht so sehr variieren von anderen der Gegenseite

also about our new orders from above which don't different all that much from those on the other side.

[hero.]

Hello Richard !

The first part is a typical german phrase similar to :
Na, da könnte ich euch einiges erzählen ...
or
Da könnte ich euch Dinge erzählen ...

It always implies something like ... das glaubt man ja nicht ... (you won't believe it),
but that second part is typically left out.
So it refers to something, one reacts to with a head-shaking !

A possible (but still not satisfying) translation could be :
I could give numerous examples, ...
or
I could tell you some examples (stories) (but you presumably won't believe them), ...

I hope that gives an idea ...

Best regards,

hero.

[fridgeman]

Hero made already some good points to explain it, i just have an addition.

In this case the author seems to have a negative opinion of the new orders,
as he uses the phrase "Es ließe sich allerlei sagen", which means "It could be told all kinds of (bad) stuff about...".

This phrase is used when the things you want to say about something are very negative, but you dont want explain it more.
The author had no good opinion of the new orders at all, so he not only compared them with enemies orders, but also
used this phrase of rejection.

[Richard Hargreaves]

Thank you gentlemen for the detailed explanations - that makes perfect sense in context.

The extract comes from Helmuth Groscurth's letters which are littered with criticism of the high command and lack of moral backbone of the Officer Corps.