Written in 2018
I collected here what changes I noticed when replaying both games just recently. These might not be all of the changes, but they're the ones I noticed. I split the topics up into good, bad and neutral.
After I first went to an inn, I was really surprised that the new dialogue scenes promised upon release of the remake all happened before our heroes went to bed to refresh their HP and MP. In the original game, this was just a method of healing up, where as now going to an inn provides some time for the characters to reflect what they're seen and experienced.
Often enough, these scenes are silly and sometimes questionably funny, but overall it gives the story more depth and the cast more personality if they talk about where they have been, which monsters they've slain or what magic they have cast.
It's also interesting to see how the bond between the characters strengthens throughout the story.
Many people consider the soundtrack of the remake inferior to the original game, and I have to admit that some tunes are quite weird. Still, in the end you can notice on every piece of music that it has been created with a concept and tried to adapt to the sequence it's been played.
And still, even if you cannot live with the music provided in the remake, you can still play the game in the original soundtrack. Although you then really miss out on something!
The only soundtrack drawback is that "Dark Star" isn't played in the overworld after the mana temple has arisen from the sea.
The first half of the game, when you still don't have a flying dragon to your disposal, you travel a lot with cannon travel to reach faraway places. The cannons are brothers who all look the same and they provide a service that shoots people around in giant cannons (In Seiken Densetsu 3, you can learn how this all came to be).
In the SNES game, after being shot with a cannon, the characters can be seen swirling around in a nice zoom out and zoom in scene where they are shot from their departure to their destination. However, in the remake, no such scene was displayed.
After launched from their cannon, the view just transists to the heroes arriving in their destination. I really wonder why this decision was made since it didn't require a whole lot of time to travel with this animation.
The game overall looks rather simple, with few polygons on screen and sometimes quite blurry textures. Still, with its art style and its cutesy designs, the remake is pleasing to look at (although arguebly the original is more timeless with its pixel perfect visuals).
But some monster designs are plain ugly. As an example, look at the screenshot here where you can see the fire giant boss. It looks bland and simple, with a strange shading and color choice that makes it almost look like a design from the PS1 / Saturn era.
Once you've got Flammie and you can travel the world freely and fly around. In the original SNES game, the map was designed in a nice "Mode 7" 3D view (that was also used for cannon travel), but in the remake the world map is fully polygonal of course.
In the SNES game, I was often lost because the world was vast and it was hard to find out if you're above the island or place you were looking for. In the remake, the world shrank a bit, since you can now hop from one continent to another in matter of seconds.
Now the world map also shows with a little text box indication what place you're currently flying over.
I don't exactly know why, but both your party and the enemies miss a lot of their hits. In fact, "MISS" is more often to be seen than the number that actually indicates damage inflicted.
This is almost a "bad" change, but I ultimately decided it to declare it "neutral" since I never actually feld being treated badly by the game. It's just as if the game developers wanted to prolong Secret of Mana a bit.
What's indeed a bit annoying is that the damage queue seems to be broken sometimes and damage dealt to downed foes isn't deducted correctly.