Ight If your gonna play this game FAST you gotta do it right so here's the levels that you absolutely have to skip if you want a decent time along with some tips. Waves with a "( )" around them aren't necessary for getting a decent time but they are the extra levels that I skipped along with the the main ones to get sub 17.

Pluto: Waves 4 & 7 If you're just shy of getting a missile in wave 6 you should be fine getting the last few in wave 7 but try to do it ASAP since if it takes too long you'll have to reset.

Neptune: Waves 16 & 17 DO NOT SKIP THE ROCKS.

Uranus: Waves 25 & 27 The rocks are also not to be skipped.

Saturn: Waves 34 & 37 (35) If possible try to skip 35, but if you can't that's fine.

Jupiter: Maybe wave 47? You don't NEED to skip any waves in this chapter, however there's a 3-ish second time save skipping any wave in the chapter. It's really important that you leave that chapter with at lease 2-3 missiles.

Rocks: Dealer's Choice Pick one wave and skip it, it doesn't really matter unless you have less than 3 missiles at the start of the chapter. In that case don't skip any.

Mars: Wave 64, (66 & 67)
Yup this is why you need to hold on to at least two rockets.

Earth: N/A No rockets needed. Just play good

Venus: Waves 86 & 87 (85) It's faster to also skip 84 but it's not needed unless you're going for the record.

Mercury: Wave 94 (95-97) 94 at its best is as harmless as any other rock level that I say not to skip, but at its worse it's the longest wave in the game. Not Worth/10. Aside from that if you can try to skip waves 95-97, but make sure you have at least 1-2 missiles saved.

The Sun: 105-107 & 110 (104) By wave 104 you should have at least 4 rockets. 3 for 105-107 and one extra for clearing the chickens in the 3rd act of the final boss.