The bonus content for the pre-orders of METAL GEAR SOLID: MASTER COLLECTION Vol. 1 includes:

[3 Additional tracks to the Digital Soundtrack]
・THE BEST IS YET TO COME (Master Collection ver.)
・CAN’T SAY GOODBYE TO YESTERDAY (Master Collection ver.)
・SNAKE EATER (Master Collection ver.)

More details on the official game page of METAL GEAR SOLID: MASTER COLLECTION Vol.1 Pre-Order Bonus ...