My little boy is 5 and loves watching telly - children's channels and cartoons.
He also used to love a couple of films, like Cars and WallE which he watched dozens of times in total.
I was so excited for his first cinema trip and we saw Puss in Boots, which he loved so much he went back with DH and watched again the following week (kids club - 90p tickets!) Then he saw Muppets with DH which he came back not very enthusiastic about and DH said he'd wanted to leave (but ok, maybe too old). Then I took him to see the Aardman animation Pirates one (this was all quite spaced out btw) and before we'd even sat down he started crying and saying he wanted to go home. He didn't seem scared (it's not scary and had only just started in any case) but just he wanted to go home because he 'loves being at home'. Same thing when we went to see Madegascar 3, except he was very, very upset. He was sitting with my mum while I sat with my daughter (very packed) and started crying his eyes out, even though he was there with other children who were all having a good time (two younger than him).
I thought maybe cinema was just too overwhelming and decided not to go for a while. It seems to have progressed though, and even DVDs he is upset about now. If I produce a DVD he'll immediately start getting upset and saying he doesn't like it. We've watched a couple as a family (with him free to come for cuddles or go and play in another room if he wants) and he always starts to cry in the middle saying he doesn't like it (usually when the action is at a peak) and then at the end he'll say he liked it and it was a happy ending, but will still be just as resistant the next time I suggest a film.
Should I just leave the whole thing till he's older and more mature? It seems a shame as he does love telly and movies are such a pleasure in our house.
Aww poor thing. Maybe he is just overwhelmed by strong feelings (especially as you mention he gets upset at the height of the action) and doesn't enjoy it. But then looking back on it and knowing there is a happy ending he does have a positive view of it, but not positive enough to want to go through the strong feelings again when faced with a new film/DVD?
I'd say don't push it. He will come back to it when he's ready and as it tends to be with these type of things, if you force it it usually ends up worse. Just keep watching films as a family but give him the option to play in another room as you were doing.