It's based on a wonderful Authors book, and the poster is a blatant rip off of the most Prolific British film of the last twenty years, which just happens to be another Welsh source.
The problem? The maker is no Boyle, and the star is no Obi Wan.
It tries from the offset to be as hip and cool as Trainspotting, but Boyle brought out the sympathy in the main characters, and made them to a certain extent, likable.
Here, they are just spoilt, and for the most part under the influence. Here Lloyd is the protagonist, and he's very annoying from the moment we meet him. The initial opening is very good, but as soon as we join Lloyd on his journey, he becomes annoying, a lot like people on the titular drug.
Other characters are just as bad, and we have the bloke from Pontypool in other scenes just to bring the film back down from the ecstasy cloud.
If you are a fan of Welsh, this will make you angry, because his poetic words here are trounced on.
Remember, look at the poster. If you think of Trainspotting, you know to avoid this.