This is a hack made by user ridtrikaplz that changes the music for Mission 27 Claustrophobia from "Mind Flow" to "Defiled." References for this improvement are the OST booklet and the export release, both of which have Defiled as this mission's BGM.
While this improvement was made for Project NEMO, an English fan-translation project for Ace Combat 3: Electrosphere, it is being made available separately so that JAPANESE players can enjoy this particular mission with the correct music as well.
To install this hack, simply use CDmage to replace (Import) "ACE3.BIN" with this BIN file.
SLPS-02020
Size: 716,287,488 bytes
Size on disk: 716,288,000 bytes
CRC32: CCDDA3B5
MD5: 30F7DCE98B6901290CB26C9BAF27268F
SHA-1: 8C6D58308EB389A7B18BC213A6D1E23D14FD3C10
SHA-256: CFDEC8640CFB0FE5C1AD1AD8C76C958D756FBE75D73E1F449D468EBBAFB8D60F
SLPS-02021
Size: 723,813,888 bytes
Size on disk: 723,816,448 bytes
CRC32: B86E0F52
MD5: 50760963AE8A26EA0188B165F05B33A1
SHA-1: A23E046B1EB695E02D214D269FCA70DBE0A437F7
SHA-256: CFD9CD36BA858AA81927306EC761A228C8E88BE48F1B1DB9AC9D7F2BDBE8C854