I'm not worrying about the final boss--his name's Chaos, in case you're curious--at the moment, though; instead, I'm focusing on the game's four, 100-floor bonus towers.
They're quite challenging, as I'm sure you can imagine. For starters, the layout of each and every floor is randomly generated. Also, every 20 floors or so you're forced to battle a boss.
This guy reminds me of Professor Layton for some reason.
It's not all bad, though, as each tower has a special shop on its 40th floor, and treasure chests--filled with rare weapons and armor--are located on each tower's 70th and 90th floors. Oh, and you receive a crown--four total--every time you beat a tower's 100th-floor boss.
So far, I've conquered the first tower and made it to the 40th floor on the second and third towers. I may take another run at Chaos after I complete the second tower--or maybe I'll just stick with the bonus towers until I get sick of them...