I wanted to try an illustration that told more of a story that isn't just people shooting at things off screen.
Also I wanted to try doing more post-processing on the image once I had finished painting the image. The effects are all achieved with adjustment layers (which can be found on the bottom row of the layer's window in photoshop). These can help push the value range, colour balance or even change/replace whole sections of colour in the image. Very useful for getting that little bit more out of any paintings done.