Can PvP and PvE Coexist in the same game?

[Angerak]

In your game, how many actions can a player take, before the other player(s) can respond?

A player can move any/all of their playing pieces on any given turn.  What each piece can do depends on the type of piece and the skills (for characters and agents) the piece might have.  I fear that is an exceptionally vague answer, but a detailed answer might be too long for a single post.