The World Ends with You: Solo Remix Tips

Getting Shadow and Dark Matter
A quick and easy way to get the most elusive pins in the game.

Dark Matter:
Requirements: Ultimate Mode, Chain 16 (Recommended), Level 80 (Recommended)

Set your difficulty to Ultimate and set your drop rate to around 30 (around 25 if fine though- no less!). Then, go to Week 1, Day 4, and when you're allowed a break from the dialog pick your partner of choice (but remember that you will fight Reaper Beat with Joshua no matter what), then scan while at the left side of the area. Touch the boss symbol first and then touch as many other Noise symbols as you can (don't worry; when you get to them, they'll be easy).

Fighting Reaper Beat:
He's insanely fast, making projectile attacks fairly inaccurate, so opt for pins that bring Neku close to him and guarantee a hit. I use(d) Shiro, Healing Bunny, Boomer, Rhyme (sub pin), Kanesada, and Tin Pin Blade. All of Beat's attacks are physical, so you'll know when he's attacking and when you're in danger. Remember, this doesn't have to be pretty, you just need to hope that, when the fighting is over, it's a large red pin that you collect.

Finish off the Noise, which at this point is even easier done than said, and you'll have collected a Dark Matter pin.

Shadow Matter:

Requirements: Ultimate Mode, Chain 16 (Recommended), Level 80 (Recommended)

Set the difficulty to Ultimate and go to Week 3, Day 7 (actually, you can do this on any chapter with Taboo Noise, but W3/D7 allows you to go pretty much anywhere you want, so it's not necessary to go to Another Day), and go to an area with Taboo Noise. Pick the partner you're most comfortable with, then scan.

Once a Taboo Noise or two gets close, start chaining as many other Noise as you can. There's only a low, low chance of the Taboo Noise coughing up Shadow Matter, so the higher you drop rate, the better (I managed to get about 4 of the pins (in one try) with my drop rate at 30 and only chaining two or three battles, so don't worry.).

Kill the Noise and hope that it's large red pins you're picking up.

(Please note that I DO NOT prefer or recommend this method.)

Go to Week 2, Day 7 and head to Shibukyu Main Store. Scan while around the middle of the area, touch the boss symbol first, then any other amount of Noise you want. (WARNING: The boss will be powerful.) Put your drop rate high; Shadow Matter is still rare.

Now, you'll be fighting Minamimoto (first time you fight him), but he's NOT YOUR TARGET. Instead, you're aiming for the Taboo Noise he spawns. Keep killing the Noise as much as you want and ignore Sho, and keep watching for the red pins. You can get an unlimited amount of Shadow Matter this way, but remember that your inventory will cap it at 99. Remember that Minamimoto is difficult to beat, so go into battle EXTREMELY WELL PREPARED.

Hope this helps.