Sami, here are some pictures to explain what I mean.
1)
What about this path instead of going up? This way you don't have to kill any bees. I am not sure which way is faster though, but SpiDeY mentioned it and I agree with him.
2)
I think we are talking about different levels. Anyway, I was saying you don't have to run or jump "through" anybody. For the first guy, if you jump a little earlier, you can land on top of him, which I think is quicker.
3)
I wasn't talking about normal jumps exactly. What I mean is, you know how Rattly hops along while "walking"? You can do a short hop and normal jump from the height of the hop (shown here), and this clears many of the jumps where you use A. This might also be useful in other Rattly levels.
4)
After you go through a small gap to the left, you can then go through this gap here while going down. This is faster than going around to the far left, which is what you did.