In order to practise I’ve been playing many games on Japanese and some tend to be harder than others so here’s what I think of the difficulty in reading and listening for each individual game I’ve played
The World Ends With You (Android): Fairly easy, given the urban setting characters use a lot of slang but nothing to obscure for anyone who has watched one or two anime.
Pokemon X&Y: Also quite easy, You can play this game with only kana but in my opinion it only makes it slightly harder, also there are spaces between vocabs and particles making for smoother reading
Pokemon Sun and Moon: Same deal with X&Y but given the relatively more complex story it has more complex dialogue compared to its predecesor
Phoenix Wright Ace Attorney Trilogy: Surprisingly easy to understand, I guess that’s due to the amount of detail they have to give the player in order to solve the cases, also it doesn’t use many complex Kanji resorting to using certain words in Katakana instead.
Bravely Default: A bit manageable for those in the lvl30+ area, you have to deal with the ocassional old language but overall this game is easy to follow thanks in part to most of the dialogue being voiced.
Zelda Breath of the Wild: Okay this game is very daunting vocabulary wise, it uses a lot of the old language mannerism so I wouldn’t recommend playing this game in japanese your first time through unless you perform very well on the N1, yes it has furigana but to me it’s only a needless clutch and it’s only useful for people familiar with the words but not the kanji, which is the opposite of what I think most people that study here are.
Mario Oddyssey: It’s a very simple game story wise so simple dialogue and vocabulary are to be expected, it has furigana like Zelda but again, I hardly find it any useful.
Disgaea 5: Medium high level of vocabulary and grammar but it’s easy to at least get the gist of the story thanks in part that most of the dialogue is voiced, however two characters in particular tend to speak with honorific mannerism which can make it a bit hard to follow what they are saying, there is also the ocassional modern slang that it’s a bit obscure.
Stardew Valley: This game is interesting because it’s actually translated from english so you get to see western style writing translated to japanes which is both fun and easier to read given that you don’t have to deal with much if any slang or proverbs.
Okami HD (PC): LORD HAVE MERCY! This game is set in ancient Japan so the majority of the dialogue if not all of it is of old tradition, on top of that there are many characters who speak in honorifics so you have ancient honorifics on top of ancient language and the only way to mitigate this is that the game has furigana but in my experience it doesn’t help because it uses a lot of vocabulary I’m not even familiar with on top of using alternate older kanji for common words.