I'm not knocking them: if they want to do it, it's up to them.
我不是在说他们的坏话：如果他们打算做这件事，由他们决定。
《柯林斯英汉双解大词典》
2
The idea is to kill all the pigs by getting things to fall on them, knocking them to the ground or blowing them up (the colour-coded birds have different abilities).
I love the convenience - I'm happy knocking one up out of the ingredients to hand while I'm working - and I don't care if it is a complete myth that the Earl of Sandwich invented it while gambling.