Integrating Google Maps data to a game. How?

I recommend starting with this tutorial.

http://www.vogella.de/articles/AndroidLocationAPI/article.html

That will get your feet wet in loading up maps.

Then use this tutorial at the bottom it will reference itemized overlay which will enable you to add all the weapons and respond to events when you click on it.

http://developer.android.com/resources/tutorials/views/hello-mapview.html

Your game sounds fun!!!

You can check cloudmade's specialist tools

Also there is static maps api from cloudmade

U can check a list of apps/games made using this here