Grab what you need!
Artemis Entity System takes a way a lot of the lifecycle management, and composition is a natural match for a time constrained Jam. While made in a rush, I hope this code gives you an idea or two how to benefit from using an entity system in your project.
While the meat is with peeking at the systems and components, you might like to compile the game! The project was created using libgdx-setup (not libgdx-setup-ui), which uses gradle for build automation, and snapshot versions of artemis and libgdx.
gradlew desktop:run should run the game. See the libgdx wiki for how to use gradle with your ide.
Code and graphics are under a separate license. Feel free to do whatever with the code, the graphics however remain copyrighted and are restricted in use anyway, since it's a demake of a commercial game (Natural Selection 2).
*"Left by his team, this marine has been naturally selected to defend his commander from waves of Sulks and Gorgels. He must juggle his natural desire to shoot things with an overzealous jet-pack and resource greedy turrets!" *