All fans of simulation should definitely try to play the game Fort Builder Sandbox. You will be able to build, dismantle and build again your own fort, train in it with different kinds of weapons and all this in the "online" mode.
A simulation game for fans of shooting
Three construction options, a variety of weapons and the ability to train in different environments, all in the same game. Use WASD to move the character, right click to aim, left click to build the fort, keys 1,2,3,4 to select weapons and space bar to jump. Build, train, fantasize, win, enjoy the simulation game and pump up your abilities. Time will pass without a trace, and vivid impressions will last for a long time!