In half-term, I went to the cinema I saw Early Man it was great!
In this example, there are actually three ‘chunks’ (clauses) that all make sense and need to be split up (using a full stop or a dash or a semi-colon):
In half-term, I went to the cinema. I saw Early Man – it was great!
The sentences could also be joined with a conjunction:
In the half-term, I went to the cinema and I saw Early Man – it was great!