Hell Let Loose is a multiplayer tactical first-person shooter video game developed by Australian studio Black Matter and published by Team17. Players fight in iconic battles of the Western Front (and now Eastern Front too) of World War 2 at the platoon level. Matches are 50 vs. 50 combined arms battles between two teams, each consisting of multiple smaller rifle squads of six soldiers, armoured squads of three soldiers, or recon squads of two soldiers.
The playable maps in the game are designed based on historical WWII theatres of war by combining satellite imagery, archival aerial photography and street-level recreation. According to the developers, the map for Norman town Sainte-Marie-du-Mont is "a 1:1 scale battlefield" recreated through the aforementioned methods.
I started watching a few YouTube gameplay videos yesterday and ended up being hooked on it for hours. I'm not sure yet if I'll be playing it myself, but just watching the games unfold is incredibly immersive. Obviously team play is a central part of it as for a tank you are a crew of three humans having to work together. The video I've linked to below is actually a tutorial for beginners to just give an idea of some detail involved, but it is really worth watching some gameplay videos.
See Hell Let Loose - !!NEW!! GUIDE to EVERYTHING (Update 10) 
Here's EVERYTHING you need to know about Hell Let Loose. This is a complete guide for beginners, covering everything from tanks to spawn points, use of suppl...