I dug back into some Pokemon Diamond on my Nintendo DS emulator last night, and I managed to defeat two more Gym leaders known as Maylene and Crasher Wake (more like Crasher Cake 
). So far I have obtained four badges and made some good Pokedex progress by catching various types of Pokemon that I haven’t even seen in-game before like Skorupi and Carnivine (both located in the Great Marsh) 
Now I just need find a way to get to the Team Galactic HQ so I can search for Dawn’s Pokedex, which she accidentally dropped on the ground somewhere in Veilstone City and was stolen by Team Galactic. Uh-oh!
But either way, it was fun destroying opposing trainers and Gym leaders.