Maybe you want to show off a cool move.
Maybe you want to rub the player’s nose in a failure.
Maybe you have a gameplay reason…
Replay is a cool videogame feature that is definitely a thing that is harder than you think
There are 3 ways to approach replay from brute force to elegance
Turns out, I have a bias on this one…
Chapters:
0:00 Intro
0:20 Screen Recording
1:44 Replication Recording
4:14 Input Recording
6:21 Use What You Have
6:52 Options Based on Your Choice
7:47 Which Would I Do?
Source
Great video. I built the replay system for Dota 2. It uses your second method of recording changes. For seeking, the server dropped "key frames" which is the entire game state for all objects every 30 seconds in the replay. This allowed seeking by finding a keyframe before the seek point then running the replay to the frame you seeked to. It also supported backward compatibility so that old replays could continue to be played even after the game was patched extensively–this was done by dumping the replication tables at the start of the replay and then hooking them up on playback ignoring added/missing fields. Old replays may not play back perfectly, but would function enough to see what happened.