Smacked in the Head by Sean Krummel 
This is the Krum's World alternate cover
 
Chapter 2 of an ongoing adventure.
 
THE LAST WAR: Mankind’s inauguration into space was not one of scientific discovery but a baptism of war. Like a message in a bottle, radio telescopes trumpeted our existence across the vastness of space and great mechanical ears strained in response. Our search for other life told whoever might be listening who we were and more importantly where we were. For the most part the message fell on an unreceptive galaxy too consumed with fear and paranoia to bother with a fledgling race yearning to explore. But someone was listening.  
 
The Adventure
The Somarian Military Conscription Act has gone into effect and the sons of the colony world are unjustifiably forced into a war that they have nothing to do with. Having lost two of his brothers to the draft already, KRUMM's parents take steps to smuggle their youngest son off-world aboard the freighter of an old friend with specific instructions not to return until called for.
 
Three years later, no word has come and KRUMM has grown impatient. "Borrowing" a ship, he returns home to find a world very different from the one he left behind. The city and towns of his childhood are ruins crushed beneath the foundations of huge alien structures, as fat guns squat in the forest shooting anything and everything out of the air.
He begins the desperate search for his missing parents while uncovering clues as to what has happened on his home world. The answers he discovers will send him hurtling across the galaxy risking life and limb on adventures he never could have imagined.