Koridora

Too hard. Bad for casual people. 

At least make Stage 1~7 not so tryhard.

Maybe add more revives and reduce boss' HP and Defense by a significant amount.

Or add a way to craft Red Crystals using low tier ones.

My suggestion:

1. Get rid of Beelzebub Stuff.

2. Get rid of Yod Stuff, after you're done crafting all Yod's customes (except for the material that can be used as trigger fuel)

3. Keep the costume silks or sell them.

4. Save all Tiamat-related stuff.

I believe that the cost for the tuning plugs and equalizers should be nerfed. They're actually quite expensive compared to the rest of the stuff in the event shop.

Other than that, event seems pretty solid.