No need to make films like these I get it... there are Ryan Reynolds's fans and nostalgic viewers that feel like watching cheap unrealistic scifi with weak plotlines done with current technology. But the rest of the film watchers don't deserve to be put through such an ordeal.
The storyline is either too simple or incredibly complex: Go back in time and change the future, in this case by destroying time travel. By now, so many films have been made on that, many quite memorable, that it could be quite interesting to see in which ways the scriptwriter solves problems like: what happens with the memory of people that time-travel? This film always chooses the worst and silliest solutions, for instance: they just forget everything. Ok...
Then we have Reynolds playing the smart guy, Buffalo playing the scientist, and so on... so we get the idea: come and play what you did in other films. Young Adam is probably the most successful character, quite cheeky, entertaining and fresh.
The film does take some breaks in the action, for the father-and-son conflict mainly. These parts are quite boring an cliche, and I guess not many people would feel moved by it.
Is it worth watching? I regret having done it. Those of us who have watched low-budget, poorly-scripted films in the 90s are left wondering why we end up watching a film like this. I guess that the audience is constantly renewed and each generation wants to regret having watched horrible films like this when they were young. So... help yourselves.