Sandstorms a' Brewin'!
All of the battles fought in the desert of Route 4 and the Desert Resort will have a constant Sandstorm weather effect, which inflicts 1/16 a Pokemon's max HP in damage each turn. Equip the Leftovers you hopefully picked up in the Castelia Sewers or use Rock-, Ground-, or Steel-type Pokemon, who are unaffected by the sandstorm's damaging effects.
|Sandile||/||Lv. 14 ~ 17||35%|
|Darumaka||Lv. 14 ~ 17||35%|
|Trubbish||Lv. 14, 15, 17|
|Minccino||Lv. 14, 15, 17|
Route 4 (Black 2)
From the start, you'll see that there are quite a few buildings in the area. There's a Hiker and a PKMN Breeder really close by. The PKMN Breeder uses a Drilbur L16 and a Marill L16, while the Hiker won't battle you. Keep in mind that the PKMN Breeder will battle you again each time you enter the route! Go on forward and then Colress will show you a bunch of Crustle, then use some kind of thing that makes them scurry off. Neat! But afterwards, he's going to battle you!
After beating him, he'll say a whole bunch of stuff, and then will give you a Protein to help boost your Pokemon's Attack.
Head on over to the west, sneaking through the buildings (you can actually do this before getting your Insect Badge), and you can fight an Officer with a Growlithe L16 and a Herdier L16. Take him down, then head further west until you see some steps. These steps lead down to two Fisherman and a Mystic Water. The top Fisherman has a Basculin L17, while the bottom one has a Psyduck L16 and a Basculin L16.
Now, head back to where Colress was and head north. There are a whole ton of buildings. The first building on the right has two Ace Trainers; the girl will want to see a Pokemon with a high enough Speed stat. If you show her a Pokemon with a Speed stat higher than that amount, she'll give you a Health Wing; if you show her one with exactly that amount, she'll give you five instead. You can do this each day, and it'll change the number you need to show. The second building on the right has a lady inside who will trade you a Petilil for your Cottonee. Since you can't catch Petilil in Black 2, this is a good trade if you want to get one. Plus there's also a Wide Lens upstairs in that building, which increases the accuracy of the holder's moves by 10% of their base accuracy (i.e., 70% becomes 77%). Very handy for Scraggy/Scrafty to help with its Hi Jump Kick.
Head further north and enter the building on the left. Upstairs, you'll find a Black Belt that will give you a generous 3 Sitrus Berries. Exit the building and keep going north. There's yet another building on the right, right by a fork in the road, so go inside and talk to the lady in there and she'll play a game with you, where she'll make the cry of a Pokemon, and then you need to guess which Pokemon it was; if you answer correctly, you'll get a Poke Toy which can be used to run from a wild Pokemon fight (though it uses up the item). Presumably you can do this once per day.
At this point, after exiting the building, you can either head north towards Nimbasa City, passing through the Join Avenue first, or you can head west to check out the rest of Route 4 as well as the Desert Resort. If you want to check out the rest of it, keep reading on, otherwise click the button below to continue on to Nimbasa City (you'll have to come back to the appropriate page in the walkthrough if you want to check it out later, though!).
So, continuing to the west (you brave adventurer, you!), you'll find an Officer with a Riolu L21 and a Growlithe L21. Past him, continue to the west and you'll find a little house that you can heal up your Pokemon in if you talk to the guy inside. See the lady nearby? She leads up to the Desert Resort, so you can feel free to check that out now, but I'll return there after showing you what else is on Route 4.
Head south of her, down the steps and into the sand pits. There's another Officer, this one using a Herdier L22. To the left of him, up the steps and hugging the edge of the cliff, you can find a hidden Red Shard. Go back south of the Officer and you'll also find a hidden Hyper Potion in the sand.
Go over up the stairs to the right, then walk through all of the sand to find the ever-useful TM28 (Dig), which is a strong 80 power Ground-type attack that a whole ton of Pokemon (even non-Ground-types) can learn, so definitely take a moment to see if any of your Pokemon can learn it.
Taking the steps to the left instead will lead you to two Roughnecks. The one on the top uses a Darumaka L22, while the one on the bottom uses a Venipede L21 and a Sandile L21. In the top-left corner just past them is a hidden Stardust. Then there's a Biker with a Zubat L21 and a Timburr L21, and a Youngster with a Pidove L22 nearby, as well as a Grip Claw held item, which isn't all that handy, sadly. Through the fence to the east, in the sand, is a hidden Yellow Shard as well as a hidden Stardust just past it.
Finally, just south of them is a band of Hooligans that will fight you in a Double Battle with a Cottonee L21 and a Petilil L21. There's an empty space to the east of the Hooligans (except on Thursdays; see the notice below), but to the west of them is a hidden Green Shard.
Mandibuzz Madness on Thursdays!
If the clock on your DS is set to Thursday, you'll run into a Mandibuzz sitting by the fence in this part of the desert! This Mandibuzz can be fought if you talk to it. It's at level 25 and has the Secret Ability Weak Armor, which lowers its Defense one stage every time its hit by a Physical-based attack, but raises its Speed by one stage afterwards. This specific Mandibuzz is only available in Black 2, just like all Vullaby and Mandibuzz. It's really convenient, though, because you couldn't normally catch Vullaby until towards the end of the game in the original Pokemon Black, and even then, it didn't evolve until level 54.
Alright, that should be all of the extra parts of Route 4 to explore, so you can now choose to go to the Desert Resort for more exploring, or you can head on over to the Join Avenue in order to make your way to Nimbasa City!