I don't know why people don't like this...it's actually quite fun
The controls are great, very easy to learn, and feel like any other Gamecube FPS. As far as difficulty, the game can be played at three levels according to skill. On easy mode you can have a trophy beacon that shows where animals are, but if you want to make the game more challenging yu can easily go into options and turn this off. There is also a bullet camera that will show you how close you got to your target. If his makes the game too easy, this can also be turned off. The only complaint I have is the time I got my boat stuck in the ground and I couldn't get it out even after restarting the game. I had to totally restart my profile which was a major disappointment. Luckily I wasn't very far in the game.
The graphics are among the best I have ever seen on Gamecube. There is a lot of details you probably wouldn't miss if they weren't there, like your own shadow (how many games show that?), and reflections on guns. The scenery is very nice looking, and the animals are detailed and well animated.
The sound another one of the great parts of the game. Foliage makes appropriate sounds as you move through it, and the animals make realistic sounds. Once again, there are many details you wouldn't notice, like the rustling noise of your clothing rubbing.
Overall this is surprisingly a fun game. If you can find it cheap, buy it. Otherwise, you should definitely rent it.