There is a bit more detail on the achievements that hasn't been announced yet. Several of the achievements have multiple levels, we call them Bronze, Silver, and Gold. So the Bronze level is not too challenging, the Silver level is tough, the Gold level is very very tough. For example, excellent marksman is like this:
With a bolt action rifle (non-sniper):
Bronze: Get a kill at 100 Meters (Challenging, but any competent rifleman will get this one pretty quick)
Silver: Get a kill at 200 Meters (Pretty tough to do under normal gameplay, but good riflemen will get this)
Gold: Get a kill at 400 meters (Possible, but just barely. I doubt there are many rifleman that will get this one. There are only a couple of official maps that have rifles and a long enough view distance to do this, even Berezina only has a view distance of about 250 meters)
Knights Cross and Hero of the Soviet Union will take some time to get, as you have to win every map we have up on Steam as German for Knights Cross and Russian for the Hero of the Soviet Union. I think that is close to 30 maps. Please note, you have to win a MATCH, not just a round. So even on shorter maps your looking at 30mins for two rounds. I'm excited to see who get's this achievement first.
Ultimate Hero and Glorious Leader should both be pretty tough too
Our goal was to have some achievements that you can get pretty quick, and others that you REALLY have to work for.
Oh and Fallen Heroes is great fun
Its a really great combined arms map with good fun for both infantry and tankers.