I've come up with an alternative, the image in the middle, and would be grateful for any thoughts you have.
Books Magazine
I was rather proud of my Time Rats 2 cover, until someone suggested it looked like a dystopian thriller cover, and didn't go with TR1's cover. (It was really nice of her to volunteer this; most people politely keep quiet over their doubts.) I'd been fretting gently over the gun, as Amazon is anti guns on covers right now, but didn't have a better shot to use.
