I really love the game so far! The new update was pretty cool. I liked the new end sequence, and I had a blast playing it!
A few suggestions: The areas should have some more visuals and puzzles. The music tile puzzle was fun, but it would be nice to have more than just the one. And visuals is self explanatory. (I did notice that you added some visuals in the update! It's a good start, but you couldn't go wrong with a bit more.)
In the bar fight, I preferred the special attack's name in the first version. (Waterfall of red death, as oppose to Marathon of red death technique. I don't remember the name exactly, so forgive me if I'm mistaken.)
Another thing in the bar, when you talk to white mask (gaster) The music stops entirely - I think it might be better to have it stop and then resume after a few seconds.
And finally, when you confront gold pig, I noticed a small typo when he says that it's best to get rid of you.
I really look forward to seeing the game completed! It's very promising so far, and I've had a fantastic time with it.