How do 당신 unlock all the characters?

One way is to go through the adventure mode.
But a few like Toon Link are found through hidden doors.
After 당신 get so far in this mode tyou go to 이전 levels to locate them.
I can't remember the details

The long way is to just play the game until 당신 are challenged.
After so many total hours of game time a secret character challenges 당신 .
Time spent on the menu screens does not count only the time spent fighting .

to unlock sonic 당신 have to beat classic mode 10 times and the 10th time 당신 beat classic mode 당신 have to beat sonic to get him

normaly i just get them all in subspace so keep trying.

just play adventure mode

당신 unlock them:) xD

당신 can get them from SSE, but their is like two characters 당신 can't get from it (Jigglypuff and Wolf).

I usually just play with a friend and they come and challenge u and u have to beat them to get them as a playable player although most characters are in the embassy

당신 can get every character from the Subspace Emissary. Toon Link, 늑대 and Jigglepuff are found in The Ruins, The Wilds, and The Forest. 또는 something like that.

yup i have!