A very good step-up
Gameplay is both more of the same and improved. Battles play out like usual on the 3x3 grids. The liberation mission of the GBA versions are intact. I idea of the liberation mission itself is a nice new twist for the series, along with the inclusion of enemies attacking on both sides of the field from time to time. Well, the biggest change in the liberation mission is the elusive TP chips: Special items that allow you to change one character for it's equivalent in the other version (ex. Switch between Protoman and Colonel in Team Protoman or vice-versa). You can collect 4 or 5, but they are well hidden. The most significant change to battle comes as an exclusive to Double Team, which is a in sense a battle party system. Now, after new members join your team, image data will be created and allows you to switch between two other navis in battle during regular net-roaming. Each character has exclusive powers that differ from Megaman's soul form of them, including a single character specific chip that can only be used by that navi when it's battling. Each navi has its own stats and can use your folder. Once the party system is introduced, you learn that they even have a mini-navi customizer for you to beef them up. The new navis can be in play for infinite turns, but there is a limit to how many times you can switch between navis. As far as regular game roaming and menu scrolling goes, the DS's touch screen makes it simpler to navigate your PET and organize your Chip folder/pack. Also, on screen maps for the net have become available. You can view the map as you move in the net and even obstacles on the net are displayed. Megaman's position on the map is constantly displayed, allowing you to do a straight-forward navigation through net areas you've cleared. The only down side to the map is that most maps aren't immediately available. They must be collected as hidden items on the net. There are a few new touch-screen mini games that allow you win party navi customizer progs. Maps remain largely unchanged, but a few seem to have minor alteration between GBA and DS.
Graphics are not outstanding. For what was displaying DS power, namely the new PET navigation screen, nothing changed from the GBA. A 3D Megaman is always present on the screen as long as you aren't viewing the PET menu, on the net, or in battle. Megaman is largely stagnant, and only shows life in the form of a faint blink, the occasional nod during story narration, and jacking-in and out animations. A minor change that isn't outside of GBA powers is that the portraits displayed during story narration now have variations helping to express a characters feelings as the words bleep into the text box. Nothing special, but it's a nice touch of variety.
Sound definately has more life to it by being on the DS's stereo system. What's new is voice clips from the amercian anime actors. They are used in the most repetitive situations, such as jakcing-in, initiating an important battle, annoucing e-mail arrival, and when you push L-button to talk to megaman. Lan doesn't have a voice clip for that feature. Megaman and some other featured navis have voice clips for battle grunts and victory comments. The use of voices isn't spectacular, but it spices up the largely silent game.
As for bonus content, you get the party battle system with the sub-navi customizer and programs, the TP chips, a few exclusive secret battle chips, and the map data spread across the net. The voice acting could be considered bonus content too, but the touch screen interface is a real bonus. Also, plugging in the different megaman battle network cartridges in the GBA slot of the DS adds new power-ups, shops, chip traders, and even changes certain features in the game.
The package altogether is much better than the standard GBA games. Sadly, this is still a revamped port. Had Capcom taken the time to really make this for the DS, this would have turned out as a great installation, instead of a very good one. If you're a fan, buy this because of the new content and it's cheaper than the two separate GBA games.