Thank you.
Regarding the secret achievements, I guess I can reveal the requirements right here and now. The game's been out for almost 7 years already after all.
-. Click on the tip of the magic staff in the main menu.
-. Spend 2 minutes on the main menu without doing any inputs.
-. View the credits
-. Win on Hunter's Den several times without closing the game
-. Win on any stage with less than 5% health remaining.
-. Win on Snow Field using ice element and less than 10% health remaining.
-. Use Inferno in Forest stage.
-. Win on Riverside after taking 150 damage.
-. Trigger Nearly Perfect Cold a cumulative number of times.
-. Level up all elements
-. Obtain all other achievements.