I've tried to do some research on lidgren but it has proven very difficult to find an in-depth tutorial on how to use lidgren 3 to fully manage a game. I have a few questions relating to lidgren integration.
I've already made half my game. Will implementing lidgren require any extra steps such as preparation at this point? Is it a better idea to implement multiplayer early or later for future reference?
What information do I need to pass between the peers. The game is a 1v1 tower defense with minions. Will i need to pass the information of each minion between clients or can I just rely on the other peer's code to work it out. How about each bullet?
If I have a large array of minions does each minion need a channel of its own? How should i deal with this?
As you can tell, i'm still new to game development. Any help at all would be really appreciated.
You could follow this tutorial. Alternatively, you can take a look at the Lidgren site which has XNA examples.
It would have been easier to implement the networking at the start of the game, but thats not to say that won't be able to implement into your game now. It will just take a bit more work.