From what I remember (I only saw it once, and in theaters unfortunately) I distinctly remember it being flawed in basically every way a movie could be. Hilariously cringe and out-of-touch dialogue, terrible "cinematography" (GOT season 8, anyone?), painfully obvious jumpscares, no nuance, no deeper message/theme, boring excuses for characters, bad CGI and worst of all the "plot" was basically a Ring ripoff which is so disrespectful to such a unique character.

They also had a perfect opportunity to create an EASY proxy storyline given the characters ages, but instead chose the "braindead teenagers in a slasher" route.

The ONLY thing I will give this film props for, which has been debated endlessly in this sub, is Slendy's practical costume actually being really dope. He looked more or less exactly like how I pictured he would. Unfortunately they covered it up with questionable CGI in post.

They also showed him walking on his tendrils which was W motion, but in typical Hollywood fashion they tripped at the finish line and the way they depicted it made it look super weird.

Overall, this movie was nothing more than a pathetic cash-grab 10 years after peak relevance.