For those that have not seen it. Glad to see we are using HM sprites! They looked very good.
Now let's see what is of interest here:
-Score is back from IaMP, it's been mising since soku.
-Indeed the setting doesn't look like it's Gensokyo, or we are outside the border of something huge stepped into Gensokyo (A building?)
-Reimu is definitely using a portal to attack with a piano and grave makers, maybe she is using the "legends" to summon stuff?
-The spell cards and the numbers might be something similar to IaMP, someone raised the posibility the spells need a recharge time, the health bars don't have another "bar" which was something we saw in IaMP and HM so the spells might be able to be used at any time
I'm taking a guess here but it looks like the new system might be based on using the urban legends, like if Reimu can "cast" a legend by telling rumors about it, then she will be able to use it to battle, but the same legend could be modified by another characters (ie: Marisa), that's what the orbs and flames could mean in the screenshot