Maybe im overlooking it some where in game, but is there a list of what bosses drop upgrade items or is it just all of them, and the drop is that randomized? I can understand the rariety of the items, but since most upgrades have a cap on them anyway then why make the upgrades that rare. Anyways addictive game and i like it outside of that little issue. Thanks for any reply on this matter.
Each Boss page has a reward tab that shows you the drops. There is no list that I'm aware of. Please see the below example. I hope this helps.
There's a list now, thanks for the info on that tab =) http://forums.kanoapps.com/showthread.php?t=1736
I also have a list for all 4 games. It is in progress tho. http://forums.kanoapps.com/showthread.php?t=2407