DaVinci Resolve is a powerful, free option. You can drag all your clips into the timeline, right-click, and select "New Compound Clip" to merge them into one manageable unit.
Use a timeline editor to remove unwanted footage and ensure smooth transitions between scenes. g61091.mp4
For a player that supports nearly any MP4 variation, the VLC media player is a highly recommended free tool. DaVinci Resolve is a powerful, free option