I'm watching it today. Would rather call it a Western or what a lot of people dubbed "Satay Western" rather than a simple thriller though.
Subgenre I guess. Spaghetti Western is for Westerns made in Italy then dubbed back into English. IIRC there is also a Ramen Western, westerns made in Japan. Since this one is Indonesian it makes sense they would choose Satay I guess haha. Here's the review dubbing it a Satay Western: http://variety.com/2017/film/reviews/marlina-the-murder-in-four-acts-review-1202446324/
Wow This is indonesian language Looking at their place its pained me that some of my brethren living like last century. No technology benefit.. @Yukkuri Oniisan probably live in that kind of place too.
Anyway, I'm watching this film in the theater 3 hours from now. Will give my thoughts on it later. If you're Indonesian it's out on theaters today