Alright, KMetalmind's guide truly helped me out, but I feel like there are lots of things to add. First of all, this was MUCH easier than I thought it would be. I only spent about 20 hours in score mode, MAXIMUM. I did develop a few techniques in a couple of minigames which could help you get those last points you need to hit 165k, and I also got some additional tips for you.
Let's start with Bunny Hunter Mode. There are 10 levels, and five different modes to play them in where you can earn a maximum of 1000 points each. So we've got 50.000 right there, and it's actually very easy to max most of them, except for the timed ones.
The first mode you should start with is the single player score mode. You start with five "shots" (plungers, haha). The key to scoring big is to hit rabbits with all of these shots. DO NOT RELOAD UNTIL YOU ARE OUT OF PLUNGERS. If you hit a rabbit with your first one, you'll get 100 points. The second one grants you 200 , and finally the fifth one 500. This only goes for the plungers in the same "clip", so don't spam the reload button. This will break your combo, even if you don't miss. The coding actually is so stupid that if you fire a shot and reload before the plunger hits, you will only get 100 points since the game will think that the plunger is the first one of the set. Other than that, you only need to learn where the rabbits spawn and play until you get 1000 points. Some rabbits, like the sleeping ones, the Superman rabbit and the ones with bandages around their head will grant you more points than normal. If you hit the big rabbits with headshots or hit bunnies who are really far away, you will get additional points as well. Try to stay at maximum health, since the hearts give you points when you're done.
You can play the multiplayer score mode alone. Just plug in a second controller and kill all the rabbits yourself. There are more of them in multiplayer. I got 1000 on every level in this mode on my first try this way.
This is not as easy when it comes to the multiplayer time attack. You'll probably only get 800-950 alone, so make sure that a friend helps you out.
The singleplayer time attack is also hard, but it's not impossible to get 1000 on the levels. 800-950 is fairly easy to get. Make sure to destroy the saucers before the Splinter Cell-rabbits jumps out . Try to hit the missiles as early as possible. Shoot the bells and music players to make the rabbits run into plain sight, dancing. This will also save you some time.
Finally you've got the Survival mode. It's just like score mode, but you only got one heart. Be careful and play like normal and you'll make it.
This mode is by far the easiest, but also the most time consuming. Good luck!
Moving on to the dance mode. This is quite easy if you're good at Guitar Hero or playing music in general. Of course, some songs are truly hard, and you need to fully concentrate, but you should be able to get 1000 in the majority of the levels. If the rabbits seem to be moving in strange patterns at times, try to listen to all instruments in the song, since they are always following the beat of one of them. (They are often following the singer). If you learn the songs by heart it will be easier. You will need to get perfects on all bunnies (white light) in order to score 1000.
Finally, the minigames.
I will only write about games KMetalmind hasn't written about.
Bunnies are bad at peek-a-boo
When the big guy forces you to press the A, B, X and Y buttons I always pause the game just as soon I know the button is going to appear. This way you can unpause the game and immediately click the right button, thus subtracting the reaction time. This might save you a couple of seconds.
Bunnies rarely leave their burrows
As soon things get real (when there are bunnies in every hole), just move your thumb in a circular way, this way passing every hole in a relaxed AND fast, controlled manner. On the level with the pigs, simply don't smash the pigs as you pass over them.
Bunnies are oversensitive
I do not have a turbo controller, but I do have two index fingers. Alternating between them is faster than spamming the button with one finger.
Bunnies are ticklish
Grab a piece of paper. Draw the symbols as they appear on the screen. Every time a new "choreography" appears, pause the game and plan exactly how you will move so you don't have to stop to think in real time.
Bunnies have a poor grasp of anatomy
If you want a truly good score (950+), pause the game just before everything turns black, and use some Blu-tack or whatever and stick it to your screen on different important spots so that you know exactly how to place the body parts. Make sure you don't move the control stick after the time runs out, since this will for some reason give you 0 points for that particular body part. It's kinda tedious to reposition the Blu-tack...
The challenge mode isn't that hard! The ONLY one I got a final score less than 1000 points from the maximum on my first try was the one called "Rayman". This one has some hard ones in it, and also a luck based one. If you're struggling, just keep at it. You WILL make it.