Radical Entertainment has confirmed over twitter that Prototype 2 will not be getting a demo over PSN or XBLA:

@john1451 No demo – the game is just too big to share 1 tiny chunk. April 24th is just around the corner though, have you pre-ordered?

So no love for those who want to try before they buy. But really, if you know what Prototype 2 is and you’re excited about it – Does this really affect your probability of buying it?

Source: Just Push Start