The final battle starts here!!

Throw the knives into the center-pieces to break them. Hit the apples to unlock new knives. Each 5th stage is defended by a Virus - beat them to get exclusive knives!
Satisfy yourself by beating the Virus.
Yes., Beat the Virus that in a new turf
Now is your chance to get back at it.
Be careful to not hit the knives or the spikes.
Patience is Virtue.
Time your actions, target carefully and become the KnifeKid!

Can you eliminate all the strains of the Virus??