I heard the original t-rex is in this and do you see any of the original decimated park as its on the same island?
There is only 1 T-Rex on the Island (or atleast they only show one at a time) so its likely, but I don't remember them mentioning that it's THE original T-Rex from the 1993 Park.
There is a scene where they revisit the abandoned old building which is cool. You see a few cool things from the first JP movie, including the Jeeps, which they manage to take from the garage in one of the chase scenes.
All in all the movie is somewhat enjoyable. Better than 2 and 3 for sure. Bottom line is this is a 1-time movie. It's like trying to remake Titanic....boat sinks, end of movie. Jurassic Park can only have one angle...big bad dinosaur on the loose...run for your life.... and this is why they feel the need to make "hybrid" dinosaurs... sad...