Trine 3 was never finished, it ends abruptly. But 1, 2 and 4 are better. I thought 3 was fine, it has nicest music, and I didn't mind how they played with the camera angle, but it is disliked more for a good reason.
I'm not saying these are some super mind blowing games, more like small comfy adventure to play through with friends. I wouldn't really play alone, but then again I don't play anything alone nowadays, I rather watch youtube videos. I only play co-op.
Sad! Why don't you have any friends?