Crash Bandicoot: Wrath of Cortex - Rumble in the Roks strategy

Phase 2: hold straight up as you get back control, then aim at about that last vertical line again. You want to be knocked to the right by this rock, to have it knock you into the path of the one coming on the right hand side. Now stay between the top two horizontal lines and you should slam into that one, now turn around and hit the one coming from the left at about the same height. For optimal results, you must get the last hit in this phase while directly above Crunch.
Phase 3: Ideally what happens here is as you gain control back, Crunch knocks you back up the hill and you can sit in between the two rocks moving towards each other here. Then just move to whichever side you have momentum in, aiming at about the second horizontal line, and then go back for the last one. For some reason I didn't get enough height to get to the middle in time in this run, but the rest of the strategy is otherwise the same.