Easily the best game in the series. Perfect in nealy every aspect.
Graphics: For a GBA game, this has really great graphics. The explosions of everything look smooth and don't cause skips in the performance. The effects chips have are very varied and beautiful. The Navi bosses are detailed (just look at Plantman's body). The areas, both on the net and in reality, are detailed as well, as you can even determine who's face is in a picture frame.
Gameplay: The virus and boss battles are extremely fun. In the end, you'll be going around, hunting down viruses to fight. The Style change system is awesome. I love changing my second folder to how I want my next style to be. They are also all useful, none of them being a waste. The only element I hate being is Electric. The buster takes too long to charge, plus it's weak.
Navigation: The later (and from what I've read, earlier) games have net areas have roads that seem to cause mazes. The main road is solid throughout its path, not split in some areas like MBN4. The areas seem small at first, but in later areas, they are layered out in a clever fashion. The real world, now, has simple yet acceptable layouts. Scilab is straightforward, yet it still gives you a feel of being in an actual science laboratory.
Sound: The soundtrack for this game is very good. For the details of this short review, play the game yourself.
Personal Opinion (SPOILERS INCLUDED!!!): The main thing that attracts me to this game is its battle sequences. Fighting Bass after inserting 300 bug frags was the most adrenaline-pumping, sweat-making, tear-shedding, brain-storming moment I've ever had on a handheld. That barrier is near impossible to break. If you can somehow beat him other than the way I did it, you must be a master of the MBN art. But, just to help those in need, here's what I did (leave if you don't want to know how to beat him w/o breaking his barrier).
1. Make sure you're shield style and have Reflect in the Navi Customizer.
2. Equip your folder with Geddon3 and two Repair chips.
3. Put the Poison Pharoh PA in your folder.
4. Have a lot of recovery and barrier chips.
5. Be calm, get a rag to wipe of palm-sweats, and prepare a glass of water.
Now, if you can set Geddon3 as a regular chip, do so. This way, you only need to wait for Repair. If not, set Repair as the regular. Set Geddon3 up and use Repair so that his side of the field is only poison panels. At this rate, it would take 300 seconds (5 minutes) for his health to drain with no intrusions. When the chance comes, set up Poison Pharoh in the bottom-central panel. Stand in front of it and block is as best you can. Bass's health will deplete at an amazingly quick rate. Wipe your hands if you feel sweaty, as it will make battling difficult (trust me), and drink the water every so often to keep from getting a dry mouth (I find it easier to battle when hydrated). Now just survive the battle until he goes *Boom*, listen to Lan's funny yet creepy joke near the end, and claim your right as the most powerful being in the game (for now). You may need to practice this a few times, because knowing where his attacks hit requires a good eye and super quick reflexes. No joke. Do not attemp if you have heart problems either. This really gets the heart going, no matter haw cool you may seem.
Now the funnest battle of the game is over, and to relive it, you need to restart. Good luck getting there again.