I still haven't finished the full campaign, I'm almost done. The main reason is because the refill. I'm impatient. I posted before that I'm okay with the refill, yet I read others don't like it. I been doing the campaign one section at a time. First the DRY Lands, in hard and insane. Same process, Scavenger Pass hard then insane. Next Silent waters Hard then insane and so on. I'm at the end of DANGER ZONE in insane, with no refill. I have to wait. So my Idea is that you get more fuel credits as you advance. There are two ways of doing it "all easy, then hard, then insane." The other way is to finish each section in easy, hard and insane before you move on to the next. Now as you move on each section fuel credits rise. So, basically not enough. So here is the Idea, when complete one section, your fuel credit increase by 5. So lets start at 20 in The Dry Lands. That's all you need really. When complete Dry Lands in all 3 levels, your fuel gauge rises by 5. Now you have 25 fuel credits in Scavenger Pass, Silent Waters 30 fuel credits, Frozen Abyss 35 fuel credits, Lost Valley 40 fuel credits, The Danger Zone 45 fuel credits, and 50 for Overlord's Den. Just an Idea for those Impatient like me.