The Mirror Cube 4x4x4, is a cmbination of the Mirror Cube and the Rubik's Revenge Cube. It has the exact same mechanism as the Rubik's Revenge, but it also shares the same idea behind the Mirror Cube - Meaning same color stickers but changing block sizes. Solving the Mirror Cube 4x4x4 is exactly the same as solving the Rubik's Revenge Cube.
The center pieces of this puzzle (4 center pieces for each face of the puzzle) all have the same height and width, they only differ by depth, so matching them means there are no "bumps" - all 4 have the same depth. Each edge piece of this puzzle appears twice, and they should be matched together. After matching both the centers and the edge pieces, we are left with a puzzle that can be solved using the standard algorithm (with 2 parity cases).