A simile is when you compare one thing to another by using <em>like</em> or <em>as</em>. There's an <em>as</em> in the second one "as easily as sliding a knife...".
A metaphor is when you say something <em>is</em> something, not just like it. "[his] face became a white sheet".
An allusion is making a comparison to something the audience knows about, like comparing a rivalry to rock paper scissors (this particular one implies the speaker always wins).
