Which operating system? Make sure that your download isn't corrupted, the zip file should be ~7.5 GB large in total. And I hope you fully extracted the game before you tried to run it, don't just extract the executable.
I use windows and the file is 7.5 gb and I used breezip to extract the game fully.
Hm, ok. Eternum is a RenPy game; have you played other RenPy games on your laptop before?
Very sorry for late response but I got it to work so it's all good now.
