Here's a little game I made for the ludum dare 39 jam in Java, from scratch.

I used paint.net for textures, Eclipse as IDE and old sounds I got.
The theme was "Running out of Power",  you have a limited amount of power and have to use it, in a tricky way, to escape this kind of jail.

You can shoot only up and down, which uses one power.
There are power boost, keys, enemies and some obstacles.

Windows Version : 

Unzip and run the .jar or .bat files !

Unix (Linux + Mac OS): 

Unzip and run the start.sh script !

Make sure you have Java installed. 

Hope you'll have some fun :D