Almost everything I said in my review of Outer Wilds applies here. There's a few changes/additions that definitely make this a different experience, though.
The new stuff is much more explicitly scary than anything in the base game, which was a positive for me since I appreciated the change in atmosphere. Base Outer Wilds locations feel like passive, naturally dangerous places that don't particularly care if you're there or not, let alone if you live or die. What Echoes of the Eye adds feels like it actively doesn't want you to be there and is trying to make you go away, by intimidation and obfuscation if it can or force if it has to. It's a clear change in direction that fits what the expansion is trying to do, but some people will for sure bounce off of it.
The new music is as fantastic as you'd expect, with one modified version of an old song that plays once you've finished the expansion being my new favorite track in the entire game. They even managed to add a lot of new mechanics without changing your basic toolkit (ship/jetpack, probe, signalscope, translator, and flashlight), which is really remarkable after how fleshed out everything felt by the end of the base game.
The only real "downside" is the new stuff isn't super tightly integrated into what was already there, but I can't even imagine how it could have been since there aren't any gaps in the base game that an expansion could slot into. What little integration is there, though, is excellent.
Overall, a worthy addition to the original. Probably best played late in a first-time playthrough or gone back to after finishing the base game, considering the difficulty seems balanced for people who already finished the game 2 years ago.
The new stuff is much more explicitly scary than anything in the base game, which was a positive for me since I appreciated the change in atmosphere. Base Outer Wilds locations feel like passive, naturally dangerous places that don't particularly care if you're there or not, let alone if you live or die. What Echoes of the Eye adds feels like it actively doesn't want you to be there and is trying to make you go away, by intimidation and obfuscation if it can or force if it has to. It's a clear change in direction that fits what the expansion is trying to do, but some people will for sure bounce off of it.
The new music is as fantastic as you'd expect, with one modified version of an old song that plays once you've finished the expansion being my new favorite track in the entire game. They even managed to add a lot of new mechanics without changing your basic toolkit (ship/jetpack, probe, signalscope, translator, and flashlight), which is really remarkable after how fleshed out everything felt by the end of the base game.
The only real "downside" is the new stuff isn't super tightly integrated into what was already there, but I can't even imagine how it could have been since there aren't any gaps in the base game that an expansion could slot into. What little integration is there, though, is excellent.
Overall, a worthy addition to the original. Probably best played late in a first-time playthrough or gone back to after finishing the base game, considering the difficulty seems balanced for people who already finished the game 2 years ago.