Play along the perimeters of each level. Do one color at a time and then move on to the next. Nakes it considerably easier to get the extra bonus at the end for having all hives open not to mention makes it very hard to not beat the level.

found it kind of boring after the first minute

Every thousand points you gain a parachute man is released. Fly your plane over him and you get quite a large bonus

Crazy go nuts mode comes into effect when you have nine acorns left, so when you are getting low on the acorns make sure to count them because in crazy go nuts mode you are pretty much guaranteed a single combo due to the fact that you can just continue to shoot and it all counts as one. With that being said if there is a large acorn at the bottom while in the crazy go nuts mode make sure ot hit it because it adds 5000 points on every nut hit, not to mention it adds up on your multiplier.

As far as the challenge goes all i did was play the 40 wave on easy and by the 27th wave or so you achieve 25000 points or more. Easier doing it that way than continuing to play the 20 waves over and over again

Also, because i was curious before. If you clear a level entirely you are awarded with 50 points.

If you are playing to actually beat all objectives all you have to do is do a manual and a flip and repeat to build up the combo. Mind you it gets boring.