He was good at the beginning when he "wasn't Deadpool yet." He made wisecracks and wouldn't shut up. But they did sort of make up for the wrongness by giving him a mouth again. Did no one else see that ending after the credits? It showed his hand coming out of some rubble and reaching for his severed head, which apparently has a mouth again. Then the head said "shh" to the audience. That was a good enough breakage of the fourth wall for me.