What has changed since 2016?

[MrSquash]

I'm a returning player that hasn't played the game since 2016 and i'm wondering what some of the major changes have been since then. The last change I remember is laser turrets being made, more expensive, 2x2 and stronger

[Optera]

quite a lot changed:
https://wiki.factorio.com/Roadmap/History
and more detailed:
https://wiki.factorio.com/Version_history

[nog]

MrSquash, the changes are so many it's really hard to do an exhaustive list. The major ones are :
- complete change of science packs recipes and quantity (you have 7 different science packs now) so complete new tech tree
- no more needs to kill natives to launch a space rocket
- nuclear power
- chemistry have gone bigger
- belt speed have slightly changed
- belt splitters have become a fantastic and powerfull tool (configurable filter and priority at input and output)
- ...

Just because of splitters and science packs, these changes are so important that it's worth retrying the game.