How about the Transformer games on steam. I really like them and so do my 5 and 8 year old boys. Yes, they are shooting, but we are talking about robots not people. Plus they pretend the toys shoot each other anyway. They also love Minecraft and Terraria. Although in with minecraft once they found out about mods they kept asking for me to install them. They also play Supreme Commander. I wouldn't call them good at it, but they know how to put some AI's on their team so they don't get killed to quickly. They are not allowed to play any shooting people games or games with blood that isn't more than a red pixel like in Terraria. By the way Terraria has guns. But, we are talking NES graphics here not COD.