The Tower is pretty similar to Haeundae.(They're both about what happens when people ignore warnings of impending doom.) The only real difference is that The Tower's about a disaster involving fire instead of water. It's full of suspense and even a few of the actors are the same.
It has a similar premise, but the day the story takes place is different(TTower is on Christmas Eve & I3D is on a regular day). I like The Tower slightly better, but you should watch both if you haven't.
Totally different stories, but the same level of awkwardness and positive emotions, word plays and misunderstandings and one more does of awkwardness.
Both features some art whether music or Manga and a really good soundtrack.