Ironically, this is actually probably easier than getting all the time stars on the third zone; none of these are especially hard, though the very final level is fairly difficult due to the timing of the jumps at the start.
A few notes:
1) Pun's Labyrinth is easy but there's a trick to it - you need to go STRAIGHT across the first zone from left to right while boosting (you need to time the ground so it doesn't destroy you). The final area of it requires you to skip a "safe spot" - you're going to want to go straight down into the hole during one of the vertical lasers rather than hiding (it is easy to dodge out of the way, but it is a close thing).
2) Hiccups is very short and very easy. Note that after the first U-turn, you can avoid the second U-turn by jumping over onto the side thing which is all flashing red ground. Boost between flashes of the ground and get up to the area with the rolling balls ASAP.
5) Don't waste any jumps in the final level. You cannot wait for any jump; you must do every jump as soon as it is possible to do them. Note that in the area where you're bouncing off of the flashing red ground, you can take the bottom path (the easy way) to save time; it is faster. Boost the whole way down along it.
In the second part, with the lasers, you need to skip the healing thing in between the first two blue keys. Remember, you can boost between laser shots from the boss.