I once played against a guy who used to make airplane noises every time he placed his air units onto the map or moved them […] Rather than aid in evoking what was being represented by game actions, his antics reminded me all the more that I was playing a game. It made me acutely aware of the room and the table and especially my opponent, while the steppes of Russia faded further away.
Quotes about immersion
But board games usually do not offer both good immersion and good gameplay. There is a reason for that—the game mechanics themselves. To achieve real immersion, you need the player to forget about mechanics and approach the game situations intuitively, as if they were real.
Length: Lots of long games work fine and wouldn’t work if shortened: Diplomacy, Civilization, Empires in Arms. A big part of the game is the immersion achieved by the game length. It isn’t something a game needs to be “saved” from.