Additional Costumes for Elena
Beating the game in each difficulty will unlock an additional costume selectable in the Config (Right click on Elena)
Hard Mode
Beat the game on normal, to unlock hard mode. The enemies will give 2x as much damage, and the bosses will use new attacks.
Inferno Mode
To unlock the hardest mode, you must beat the game on nightmare.
Note you need the latest patch for this to work.
Nightmare mode
Successfuly complete the game on hard mode will unlock Nightmare mode.
Time Trail
Beat the game, and the time trail mode will be unlocked. This allows you to only battle against the bosses.
Unlocking Debug mode-the ultra hard way
After beating Galbaran in Nightmare boss rush...you will be fighting against Berhard...win against Berhard will unlock the Debug mode.
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