Aro both books the same? Are they re-edited or something?
I read both summaries and they kinda look like the same book, maybe with some changes.
I can't find any info on the author's official site. One of them is available in my country, the other I must buy from amazon. If they are the same book I don't need both.
Any idea?
here are summaries for both books, maybe any user here has read both and can help me

Code: Select all https://www.fantasticfiction.com/h/vaughn-heppner/artifact.htm

Code: Select all https://www.fantasticfiction.com/h/vaughn-heppner/eternity-machine.htm

[Maveth]

Looks like they are essentially the same book, but with different titles. Interesting. Perhaps Artifact has reflects and updated/edited re-write?

I'm not sure. I can't find enough details to determine it. From the other hand updated/revisited versions take more than 1 year, some authors edit their early works after 20+ years! It's not what I found for both books, 2015 and 2016.
It doesn't look like American vs. English titles of the same book either. You know, for example
The Cult of Osiris (rest of the world) and The Pyramid of Doom (US&Canada) by Andy McDermott are the same book
Someone Knows My Name (USA,New Zealand, Australia) and The Book of Negroes (the rest of the world), its original title would be very offensive in the USA if I'm not mistaken