How's everyone doing with the Challenge board so far? I've cleared quite a few, but there's still a ton I have to unlock, and several whose goal I still don't know. I thought it might be worthwhile to compile a list of all the conditions so people don't have to wonder what those "?" challenges are, and to help those who may not speak Japanese. I've compiled a list of what I know so far, but there's still some "?"s there. If you know what those challenges are, please post and I'll add them! Also, please point out any mistakes you might see.
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Row 1
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Clear Boss Battle on Intense
Clear Target Smash Level 1 in under 15 seconds
Clear Target Smash Level 4 in under 32 seconds
Score 400m in Home Run Contest
Play as Captain Falcon 10 times
Clear 100-man Brawl in under 3:30
Clear All-Star with 10 characters
Play on "Green Hill Zone" 10 times
Unlock Toon Link
Clear Boss Battle on Easy
Clear "ワリオブラザーズ" Event (#19)
Clear All-Star without continuing
Collect 200 stickers
Play as Toon Link 10 times
Clear Target Smash Level 4 with 10 characters
Clear All-Star on Very Difficult
Unlock all characters
K.O. 5 Fighting Alloy in Cruel Melee
Play 10 Coin matches
Clear "音響に咲く花" Event (#28)
Clear "デデデデデデハンマー" Event (#15)
Clear 15-minute Brawl
Clear Target Smash Level 3 in under 20 seconds
Unlock all Masterpieces
Clear 100-man Brawl in under 4 minutes
Collect all characters' figures
Clear Target Smash Level 5
Get a 10-hit combo in Training Mode
Play on "Port Town Aero Dive" 10 times
K.O. 100 Fighting Alloy in Endless Brawl
Clear Classic Mode with 20 characters
Score a combined 15000m in Home Run Contest
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Row 2
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Unlock 75 songs
Clear Classic Mode with every character
Play as Luigi 3 times
Score 300m in Home Run Contest
Play on "Frigate Orphen" 10 times
Play on user-created stages 10 times
Unlock all Melee stages
Clear Target Smash Level 5 with every character
Get a combined 400 hits with all characters in Training Mode
Clear Classic Mode on Difficult
Clear Classic Mode on Easy
Clear Classic Mode on Normal
Play on "Pokemon Stadium 2" 10 times
Unlock Ness in Subspace Emissary
Unlock Ike in Subspace Emissary
Clear Boss Battle with 20 characters
Clear All-Star on Normal
Clear "空飛ぶ海賊船" Event (#37)
Play on Melee stages 10 times
Clear Target Smash Level 1
Play as Peach 5 times
Clear "花ピクミンは咲き乱れ" Event (#14)
Unlock 50 songs
Score a combined 8000m in Home Run Contest
Clear Target Smash Level 3 with every character
Clear Boss Battle with 10 characters
Score 500m in Home Run Contest
Clear "ドラゴーン突貫" Event (#13)
Play on "Shadow Moses" 15 times
Unlock Captain Falcon in Subspace Emissary
K.O. 50 Fighting Alloy in Endless Brawl
Collect 500 figures
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Row 3
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Score 2000 K.O.s overall
Clear 100-man Brawl with every character
Create 15 custom stages
Clear "いくぞ！さんみいったい！" event (#8)
Clear Target Smash Level 2
Clear Target Smash Level 2 with 10 characters
Score 1000 K.O.s overall
Swim 100m with all characters
Clear All-Star on Easy
Play Home Run Contest with all characters
Cleary Target Smash Level 2 with every character
Play as Kirby 20 times
Play on "Norfair" 10 times
Collect 500 stickers
Clear Target Smash Level 3 with 10 characters
Clear Classic on Very Difficult
Clear "Subspace Emissary"
Clear Target Smash Level 1 with 10 characters
Clear Target Smash Level 1 with all characters
Play on "Mushroomy Kingdom" 10 times
Clear 100-man Brawl
Clear "カモン！ブルーファルコン" Event (#24)
Clear Boss Battle on Normal
Clear "キツネ狩りのオオカミ" Event on Difficult (#38)
Clear All-Star on Intense
Unlock Sonic
Clear Target Smash Level 4
Play on "Battleship Halberd" 10 times
Clear "ピンクだま潜入" Event (#3)
Clear "波導は我にあり" Event (#25)
Score 500 K.O.s overall
Unlock all music
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Row 4
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Collect every sticker
Clear Classic on Intense
Clear Target Smash Level 2 in under 19 seconds
Play as Donkey Kong 20 times
Play on "Yoshi's Island (DX)" 3 times
Clear Boss Battle on Difficult
Clear All-Star with all characters
Clear Target Smash Level 5 in under 30 seconds
Clear Target Smash Level 3
Fight for combined 100 hours
Clear "魔王降臨" Event on Difficult (#33)
Clear "天空界の大そうじ" Event (#4)
Unlock Mr. Game & Watch
Play on "Castle Siege" 10 times
Collect every characters' Final Smash figure
K.O. 10 Fighting Alloy in Cruel Brawl
Clear Target Smash Level 4 with every character
Clear "死闘、ダークリンク" Event on Difficult (#18)
Score a combined 5000m in Home Run Contest
Fight for combined 30 hours
Run Brawl for a combined 10 hours
Score a combined 10000m in Home Run Contest
Collect a combined 5000 coins in Coin Match
Clear All-Star on Difficult
Clear Target Smash Level 5 with every character
Clear Boss Battle on Very Difficult
Walk a combined 10000m with every character
Create 5 custom stages
Fight for 50 hours
Collect 1000 coins
Score a combined 12500m in Home Run Contest
Clear Boss Battle with every character
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Row 1
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Clear Boss Battle on Intense
Clear Target Smash Level 1 in under 15 seconds
Clear Target Smash Level 4 in under 32 seconds
Score 400m in Home Run Contest
Play as Captain Falcon 10 times
Clear 100-man Brawl in under 3:30
Clear All-Star with 10 characters
Play on "Green Hill Zone" 10 times
Unlock Toon Link
Clear Boss Battle on Easy
Clear "ワリオブラザーズ" Event (#19)
Clear All-Star without continuing
Collect 200 stickers
Play as Toon Link 10 times
Clear Target Smash Level 4 with 10 characters
Clear All-Star on Very Difficult
Unlock all characters
K.O. 5 Fighting Alloy in Cruel Melee
Play 10 Coin matches
Clear "音響に咲く花" Event (#28)
Clear "デデデデデデハンマー" Event (#15)
Clear 15-minute Brawl
Clear Target Smash Level 3 in under 20 seconds
Unlock all Masterpieces
Clear 100-man Brawl in under 4 minutes
Collect all characters' figures
Clear Target Smash Level 5
Get a 10-hit combo in Training Mode
Play on "Port Town Aero Dive" 10 times
K.O. 100 Fighting Alloy in Endless Brawl
Clear Classic Mode with 20 characters
Score a combined 15000m in Home Run Contest
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Row 2
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Unlock 75 songs
Clear Classic Mode with every character
Play as Luigi 3 times
Score 300m in Home Run Contest
Play on "Frigate Orphen" 10 times
Play on user-created stages 10 times
Unlock all Melee stages
Clear Target Smash Level 5 with every character
Get a combined 400 hits with all characters in Training Mode
Clear Classic Mode on Difficult
Clear Classic Mode on Easy
Clear Classic Mode on Normal
Play on "Pokemon Stadium 2" 10 times
Unlock Ness in Subspace Emissary
Unlock Ike in Subspace Emissary
Clear Boss Battle with 20 characters
Clear All-Star on Normal
Clear "空飛ぶ海賊船" Event (#37)
Play on Melee stages 10 times
Clear Target Smash Level 1
Play as Peach 5 times
Clear "花ピクミンは咲き乱れ" Event (#14)
Unlock 50 songs
Score a combined 8000m in Home Run Contest
Clear Target Smash Level 3 with every character
Clear Boss Battle with 10 characters
Score 500m in Home Run Contest
Clear "ドラゴーン突貫" Event (#13)
Play on "Shadow Moses" 15 times
Unlock Captain Falcon in Subspace Emissary
K.O. 50 Fighting Alloy in Endless Brawl
Collect 500 figures
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Row 3
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Score 2000 K.O.s overall
Clear 100-man Brawl with every character
Create 15 custom stages
Clear "いくぞ！さんみいったい！" event (#8)
Clear Target Smash Level 2
Clear Target Smash Level 2 with 10 characters
Score 1000 K.O.s overall
Swim 100m with all characters
Clear All-Star on Easy
Play Home Run Contest with all characters
Cleary Target Smash Level 2 with every character
Play as Kirby 20 times
Play on "Norfair" 10 times
Collect 500 stickers
Clear Target Smash Level 3 with 10 characters
Clear Classic on Very Difficult
Clear "Subspace Emissary"
Clear Target Smash Level 1 with 10 characters
Clear Target Smash Level 1 with all characters
Play on "Mushroomy Kingdom" 10 times
Clear 100-man Brawl
Clear "カモン！ブルーファルコン" Event (#24)
Clear Boss Battle on Normal
Clear "キツネ狩りのオオカミ" Event on Difficult (#38)
Clear All-Star on Intense
Unlock Sonic
Clear Target Smash Level 4
Play on "Battleship Halberd" 10 times
Clear "ピンクだま潜入" Event (#3)
Clear "波導は我にあり" Event (#25)
Score 500 K.O.s overall
Unlock all music
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Row 4
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Collect every sticker
Clear Classic on Intense
Clear Target Smash Level 2 in under 19 seconds
Play as Donkey Kong 20 times
Play on "Yoshi's Island (DX)" 3 times
Clear Boss Battle on Difficult
Clear All-Star with all characters
Clear Target Smash Level 5 in under 30 seconds
Clear Target Smash Level 3
Fight for combined 100 hours
Clear "魔王降臨" Event on Difficult (#33)
Clear "天空界の大そうじ" Event (#4)
Unlock Mr. Game & Watch
Play on "Castle Siege" 10 times
Collect every characters' Final Smash figure
K.O. 10 Fighting Alloy in Cruel Brawl
Clear Target Smash Level 4 with every character
Clear "死闘、ダークリンク" Event on Difficult (#18)
Score a combined 5000m in Home Run Contest
Fight for combined 30 hours
Run Brawl for a combined 10 hours
Score a combined 10000m in Home Run Contest
Collect a combined 5000 coins in Coin Match
Clear All-Star on Difficult
Clear Target Smash Level 5 with every character
Clear Boss Battle on Very Difficult
Walk a combined 10000m with every character
Create 5 custom stages
Fight for 50 hours
Collect 1000 coins
Score a combined 12500m in Home Run Contest
Clear Boss Battle with every character