So there's this chinese learning app called Wordswing. It has text adventures in chinese that are basically interactive graded readers with audio and multiple paths. A fun alternative to traditional graded readers. Used like a graded reader, these work well! I've tried some of their stories and they're good for this.
My one pet peeve with the app is that it labels SO MANY stories with Intermediate or Upper Intermediate, when they are all for Beginner Level Learners. If you're actually an intermediate reader? None of Wordswings story games are challenging. You would have more luck with the graded readers Pleco offers in the 1000-2000 character range. And if you are a beginner, be aware all the stories on Wordswing are well within your reading range, especially if you go from the ones with less characters to more. Be aware you are not an intermediate learner because you finished Wordswings upper intermediate labeled stories. They're also Beginner level reading material.
My pet peeve is when a Chinese learning material claims it has intermediate content but really only covers Beginner material. Which happens way more than I'd like it to. Mandarin Companion is a set of wonderful graded readers, which covers around as many characters as Wordswing, and is also only Beginner level material. But at least it categorizes by its own Level 1 Level 2 etc and doesnt call 500 characters intermediate.
For reference I'm using HSK levels (before they get changed into whatever the new HSK will be) as my Beginner etc categories. HSK 4 at minimum I would consider intermediate, because that's when you can start reading webnovels with a dictionary and watching shows with a dictionary and have small talk chats. Although i would still agree HSK is probably more like A2 (an upper beginner) rather than intermediate. HSK 4 is 1064 characters. Anything less than that many characters in a learning material does not seem intermediate to me.
Other possible HSK intermediate levels would be 5 or 6, if comparing them to B1-B2 with B levels as intermediate. So intermediate or upper intermediate is 1600 characters or more like HSK 5 etc. So.... at least 1000 characters covered in intermediate claiming materials at minimum... please.... and that's generous.....
Below is Wordswings labeling of their story levels:
It annoys me so much a 297 unique character story is marked intermediate. That is beginner reading material! ToT That is HSK 2...
I just. It's annoying to see the Intermediate level and think users who are beginners may master the hardest story on here and think Yay I'm intermediate then go to some language proficiency test like HSK, or material that is recommended for Intermediate Chinese learners, and be overwhelmed they did not actually learn enough yet. It would be so annoying to complete the stories on this, then go look up HSK to see if you need to learn a couple more random vocab to qualify to take a test or prepare for "the next level" and find out you're still in HSK 3. And that these "intermediate" resources were not actually preparing you for intermediate level stuff.
Related but its a reason I got so annoyed with Lingodeer last time I used it. Now I do HEAR lingodeer planned to add more to their courses. And I'm awaiting it still so if they ever do I'd like to check them out again. But for ages lingodeer claimed they'd teach languages like Chinese and Japanese to a decent level. So I would say, at minimum to HSK 4 which I consider the bare minimum of intermediate (but it's probably closer to A2) or N3, and please to ideally HSK 5 or N2. This would've made their app different, since Duolingo tends to cover about 2000 words for a language like chinese which is just into HSK 4 territory (if enough of the vocab is shared with HSK). Duolingo covers 3200 words in Japanese, a bit less than N3. Last time I checked Duolingo out it taught to A2 in some languages, or into B1 to some degree (decent in the case of Spanish or French and barely in the case of languages like Chinese).
Last time I checked (a year ago) Lingodeer only had around 900 words in chinese (so Maybe HSK 3). That is not intermediate. If you're purely picking a language app like Lingodeer, then I guess Duolingo actually covers more now surprisingly. Despite Linogdeers initial presentation seeming so promising for languages like Chinese and Japanese. Lingodeer Japanese once claimed before Japanese 2 came out that it would go UP to N3 and so contain around 3700 words. However when I actually try to look up and dig a word count I'm not finding estimates around 900. Which is disappointing. I hope in recent time they've really added to their courses and really gone up to HSK 4 and N3, but the last time I checked they had a lot less content then their goals stated they wanted to eventually have.
I think there's room in the learning app scene for more stuff that goes INTO intermediate levels, since so many apps only cover beginner level stuff. But very few apps are trying to hit the intermediate niche. Maybe they hope learners will give up after being beginners for a while:/
Apps that DO cover intermediate learner needs are mostly self created resources right now. Memrise and Anki can be great for intermediate learners, but if you want intermediate study material you generally need to make your own decks or find another learner who made intermediate decks and use their shared deck (the apps don't offer pre-made intermediate materials). Bunpro I hear covers intermediate Japanese grammar, and if so then it's the only structured Lesson pre-made intermediate course on an app I know of. Coursera offers college classes in chinese and other languages so it can go up to intermediate, but you are basically signing up for a real class not an app course to follow. Clozemaster is one of the closest things to a pre-made course just cause you can stick to it for a decent while as someone intermediate and find materials pre-made for your level. But it's a lot like anki and memrise, wirhout the benefit of user made courses that have been made Better for specific needs. And all 3 amount to SRS flashcards apps (clozemaster radio mode also amounts to at best an audio flashcard resource/immersion resource). Other apps for intermediate learners tend to facilitate immersion, which is very self directed on if you make progress or what you do, there is not much of a lesson plan to follow (I think LingQ may have lesson plan stories but I don't know if they go to intermediate or if by then LingQ expects you to find your own reading material to use in the app).
An addition: I forgot about DuReader for chinese which does genuinely have good graded readers for hsk 4-5 with audio and pinyin options, and Duoreader which is a small parallel text app with texts and audio for several languages and is based on actual novels so the reading level is definitely more intermediate (with the parallel text helping make it easier if you need resources for translations).