Although it's an idol franchise with uplifting and idealistic messages, the game and anime contains many heartbreaking moments.
- Every time Riku suffers an asthma attack. You can really feel the worry and tension amongst all the characters.
- At the same time, it's heartwarming to see that they all really care for each other as a group and demand Riku not push himself too hard.
- In the present, Riku wonders what happens to his formerly kind, caring Tenn-nii, who's now Ice King incarnate.
- The circumstances of their seperation at childhood count as well. Due to a failing business and Riku's frequent hospital visits, Tenn chose to go with Kujou to absolve their parent's debt. It's shown that Riku is torn up about this even in the present.
- Iori, the perfectionist, forgets to sing during Music Festa, an action that causes Idolish7's chances of debuting to be thrown away. After the live, Iori can be seen standing alone in the darkness backstage, before he quietly slips away. The other members try to call him after, with no response from him. When they finally catch up to him, Iori is crying, sobbing while apologising profusely.
- Tamaki and Aya's difficult childhood. Raised by an abusive, drunk father, dumped in an orphanage, then seperated. Tamaki's obsession with appearing on television is all out of his desperation to find his sister again.
- The look on Tamaki's face as he realises the staff has brought his father onto a talk show. It's one of absolute fear as horrible memories run through his mind. It's made worse considering they agreed to bring Tamaki's sister, yet they brought his abusive father Tamaki obviously hates.
- Though Tamaki is scolded for losing his composure on live television, he can hardly be blamed for such a strong reaction in the first place.
- Some fridge Tearjerker when you realise Aya's foster parents before Kujo adopted only Aya, seemingly not caring for her brother at all. It makes one wonder if they were truly good parents to Aya before Kujo found her.
- The bad blood between Sougo and his parents. Sougo's parents are the owners of a wealthy company, and are willing to spend money just to make sure Sougo's career in music won't succeed. Especially heartbreaking when you consider they knew just how much music meant to Sougo.
- The death of Sougo's uncle, who inspired his passion in music. Making matters worse is that nobody in his family actually cared, and instead laughed at Sougo's uncle for being a fool and thinking he'd succeed in music.
Part 2 (Season 2)
- Riku ends having an attack while the crowd cheers for an encore, and he's urging to keep going on because he doesn't want to disappoint them. He's physically not at all okay, and he was stubborn enough to be held down to take his inhaler because it's what's best for him. That doesn't mean the group likes having to force it down on him.
- Chapter 5 (Episode 5) has a serious case of Mood Whiplash in the background while wacky antics are happening. Tenn pays Riku a visit for an honest heart-to-heart, but it eventually amounts to Tough Love and Brutal Honesty that causes the latter to lash out in pure resentment and tells Tenn to get out. Considering Riku looks up to him so highly, the reaction is alarmingly unlike Riku at all, and the last shot we get is Riku sulking in his room, and telling himself how much he hates his brother. Meanwhile, Tenn can only look back, concerned that he cut too deeply into Riku.
- Chapter 7 comes to show how demoralizing a Broken Base can affect an idol group. Riku and Iori fans sparked infighting over who's the better Center, and it causes Riku to feel the stress of being irreplaceable and unneeded at the same time. This, in turn, drags Iori down, causing him to worry for him much more, and also causing a rift in their otherwise vitriolic bond. Mitsuki, meanwhile, comes to learn there are fans that want him out of the group, dragging Nagi's mood down with him. When two of the most upbeat members are down in the dumps, it's not hard to see why the group has hit their low point in their career, and it took a lot of coaxing from Nagi for Mitsuki to finally swallow his pride and release his bottled-up pain and frustration.