[RobertoMadrid]

Hola, Dupond,

I think you could very well use the expresion "estar cogido con alfileres". Very common in Spain. I guess they use it also in America using the verb "prender" instead of "coger". Our american friends could confirm it.

It has the sense of something that is provisional, not firm or imperpect, having defects or weaknesses.

Very common to hear from students before taking a test: "Llevo el temario cogido con alfileres"... or after: "me ha salido muy mal el examen, lo llevaba cogido con alfileres".

"El final de la película está cogido con alfileres".

To be precise, that would imply the idea of something, as I said, that is imperfect or weak, but not the sense of something hastily "added".

To include this sense of a non suitable or forced addition you can use the word "pegote".

"El final de la película es un pegote".

This is the definition of the RAE dictionary for "pegote": "Añadido hecho de manera tosca y torpe, que generalmente no guarda armonía con el resto y estropea su calidad y que a menudo tiene la intención de ocultar algún defecto".

Hope it helps.

Saludos,