The Monster Inside 100% Achievement Guide & Video Walkthrough.
The Monster Inside is a film noir gumshoe detective "audio visual" novel video game (audio in the sense of atmospheric music and not spoken word).
There are 7 chapters in all to play through, each taking 2 to 5 mins to complete and while there are speech options/decisions to make within the game they have no overall impact on the outcome of the game and at the end of each chapter an achievement will pop (one for each chapter).
Unlike the plethora of free to play anime style visual novels on Steam you can not adjust text speed or auto skip through text/chapters, you can however, if you are not a fan of the genre, click through most of the text quickly to skip through the game if you just want the achievements.
There are a couple of sections that will require your interaction within a scene, however, and skipping through as quickly as possible will still take about 10 mins, as such I advise you just sit back and enjoy the ride, it's only 20 mins long and worth your time and effort.