Trying to catalogue all the differences... Work in Progress...
Some of the differences are shown in the "What's Different in NHL'94 Rewind?" video.
I'll refer to buttons as the XBox buttons. A=bottom, B=right, X=left, Y=top.
Startup:
Alexander Ovechkin splash screen instead of the original "EA" logo and "NHL Hockey 94" splash screen.
Credits are not shown on this splash screen like in the original, other than FMOD, Arsenal, and Empty Clip studios.
Main Menu:
"Profile" entry with your xbox username (haven't tried it with a 2nd account yet to see what exactly it does, how it works with 2-player...)
The game remembers your previous setup (teams, period length, penalties, etc)
"Side Art" changes the art used to fill the edges of widescreen TVs
"Controls" shows a static image of the controls
It would have been cool if they transcribed the original manual into a "Manual" or "Guide" menu item.
"Credits" shows the credits, instead of below the splash screen
"Legal" shows legal blahblah
Controller Selection Screen
This screen is new! It's like the one in SNES and later games. Very cool.
"Y Exit"
At any time you can press the Y button to bring up a menu with the options "Resume Game", "Change Side Art", "Controls", and "Exit Game".
Exit Game takes you back to the Main Menu of NHL 94 Rewind (not your XBox/PS OS)
Ron Barr
All the arenas are called EA SPORTS Arena.
Ron is still wrong about who is HOT or COLD. For example in a game I played, Malkin was 99 Overall (normally 93) but wasn't called HOT. Guentzel was just 75 (normally 79) and was called HOT.
Graphics:
I'm still undecided on whether I like their portraits or not, the particular dithering they used. I find them a little blotchy but maybe that can't be helped. Morgan Rielly looks terrible. Auston Matthews' nostrilololololos. Some look fine.
Players have custom skin tones. There are at least 2.
Language:
The game is 'localized' and displays in your language. I've seen a French(France) version in a facebook post.
Bug Fixes:
They fixed the weight bug.
They fixed the "edit lines ratings are wrong", so that the ratings you see are the real ratings of the players that game (properly reflecting the random hot/coldness of each player)
New Bugs:
You can sometimes duplicate player in the Edit Lines menu. For example, if you play as the Leafs (No line changes mode) and set Marner as your centre, he will be your centre, but also still be your RW! On your first shift, you'll have 2 Marners on the ice. After that the RW goes away and you're shorthanded until you set valid lines.
Sometimes when you pull your goalie, he doesn't leave. And then if you put the goalie back, sometimes only THEN does he leave the ice.
Lots of people have experienced game crashes, which I suspect are due to editing lines. Such as when getting penalties.