Bummer. I assume that Vue dropped support from whatever this is formatted in (so this is probably V1 or V2), so this is practically doomed I guess.
Actually it didn't, I actually downloaded this, and, after a bit of pain trying to get certain files to work due to folders they needed not existing on my machine.... I managed to get a version with that single line changed to just asking for vue rather than vue@next.... And what do ya know? I managed to play and beat the game.
Nice, and I found out how to fix up the game on the website itself.
1: Right click the game and find the button saying "Reload frame"
2: Go to the error trying to reference "vue@next" (line should say "<script src=...vue@next></script>") [website name not mentioned just incase]
3: Select "@next" and override the contents. Create a folder anywhere you want, and save that override to the folder
4: "index.html" should have opened with a purple dot, so go ahead and remove "@next" from the script
5: Save the index.html since it wont try reading it until it's saved, I think.
6: If it hasn't fixed yet, yet again right click the game and click "Reload frame"
Should be fixed for the website version, and the developers, if they ever fix this real quick, can have it patched in like 30 seconds. If this order doesn't work, then I probably didn't say something right due to me managing to struggle on finding a solution for a while.
P.S. "Incremental Game Jam Game" will read this save properly even with the fix.
My bad for the confusing instructions; here is a rewritten step 3:
Right click the problematic line (or really anywhere on the sources page). Click "Override content". It should ask you what folder you want to save it to, so create a folder on your desktop, then select that folder. If you did it right, you should now be able to edit the contents and follow step 4. Also, the little sidebar to the left of the sources content should show the page you are in as what seems to be a piece of paper with a purple dot at the bottom right.
If step 4 is confusing; removing "@next" should be possible by double clicking where the text is, which should let you start modifying the text. Then you can remove "@next".
If step 5 is confusing; CTRL + S should work to save the index. I do not know where a save button may be besides this shortcut.
Hopefully this clears things up.