Nice... I liked...
but some points to improve...
1.) as it was said, SHIFT is not the best key to attack(I'd say 'A')
2.)the Sword up/Down is confusing, and may make the game harder, even on low levels...(Using mouse to rise/lower would be better)
I'd recommend theese Key settings:
A - Attack
S - Sheild
W - Walk Front
X - Walk Back
Mouse Up/Down - Sword up/Down
It would improve the gameplay...
But, congrats.. you've got a good idea on your hands!