It's fine to give some suggestions, as Mofu-san does seem open to it (especially good ideas or when it's things like quality of life improvements to the game). Just don't go overboard and post a new suggestion everyday, as it's a bit overwhelming. Do it in moderation and think before posting, is this necessary. Same goes for pictures.
Game development can be a long and difficult process and Mofu is developing this game by himself, so being told by someone to add new things everyday can get exhausting.
Also, at the end of the day, it's his game and all of us are just fans, so we shouldn't act entitled and demand everything that we want. We can give some suggestions or ideas but at the end of the day, it's up to Mofu-san whether he decides to implement those ideas or not.
Lastly, I'm not sure if it's because some subtlety gets lost in translation to English but the way you give some suggestions may come across as rude or demanding to some people. If you find it easier to comment using Vietnamese, just ask for things that way and we can use machine translation to understand what you're saying.
Hope that helps!😁