When you click on a spell (button at the bottom right, below the inventory) they normally last 30 seconds. With that skill, they can last up to 45 seconds.
Thanks for your feedback. The upgrade price has been significantly reduced in the latest update. To avoid unbalancing the game too much, we reduced the ascension bonus to 10%. Even with the reduction, the game pace is slightly faster now.
If you're asking us how to unlock more building like the mausoleum, you'll need 10 mausoleums to build a necropolis, and 10 necropolis to build a secret sanctuary. :)
I don't know...I've take some of the art from sites like http://open.commonly.cc/ and http://opengameart.org/ so it is possible that you saw the same art in other games! :)
 "Auto-Combat!"){kind=icon}
 "The New Idle Blacksmith"){kind=icon}
 "Defend Your Cheese"){kind=icon}
 "Idle Mine EX 3"){kind=icon}
 "Eternal Pharaoh"){kind=icon}
 "Idle Bob"){kind=icon}
 "Idle Raiders"){kind=icon}
 "Idle Blacksmith 2"){kind=icon}
 "Strikeforce Kitty 2"){kind=icon}
 "Tap Tap Infinity"){kind=icon}
 "MINE"){kind=icon}
 "Reckless Ruckus"){kind=icon}
 "Duty Of Heroes"){kind=icon}
Hover your mouse over the stats name for a quick explanation.