0.2.1 update

Added new character Ice Guardian

8 new skills added
- Solid Iceberg
- Cold Blast
- Spiky Ice
- Thorn Attack
- Press
- Thorn Skin
- Shattered
- Offense and Defense

improvement
- Reduction of sound effect amplification
- Credits page skip function

bug fix
- Shadow Slash Skill: Fixed a bug where additional damage due to stacking curses was not applied