i love the idea but it has too many crashes and why not decrease the cost of fuel for things that take 10 minutes to complete I like that fuel is easier to find than other games' special currency, it makes it way more addictive knowing that you can upgrade without having to pay like $15 for that new weapon hat you had you eye on since the very beginning 4/5 :)
I found a way to develop your minions very well, just wait until you have at least double your souls and then hit reset it takes about 10 minutes for your souls to double. Amazing concept and best idle game I've seen 5/5 and Favorited :) I can't wait for the second one to come out!! Some things I think you should include in the release of the second one are animation of the undead next to their name and evolve when upgraded ex: change in ferocity and equipment also a battle scenario so that you can fight with your undead minions. I hope this helps the format of the next one :)
http://www.kongregate.com/forums/3938-card-hunter/topics/457267-guide-shops-selling-items-chests-and-moar