A horror that looks like high-grade 1980s output, which made it spooky and nostalgic in equal measure - the 16mm explains the nostalgic bit.
On the positive, the young main characters are attractive - I dug Laura (magazine girl Anna Brewster) and her Kate Moss delivery - very London - and the set up is nicely done, hinting at yikesy things to come, which they do.
On the negative side, I wasn't really sure about the movie's central message, but I did like the hook - yes, there is a comparison to Triangle definitely, but this is different again.
I'd say that this is not a wide theatrical release type movie but that it's pretty good and quite creepy watching it late at night within the comfort of your own home. Most of the acting makes it feel very natural, very real, and you can (if you shut your eyes and click your heels three times) almost imagine yourself there in amongst those razor-sharp greeny reeds wondering where everyone else is...