Below is a link to a playlist that I've recorded.
It contains ALL world 2 and world 3 levels (apart from 70 and 74), on 3 stars, using NO BOOSTS! https://www.youtube.com/playlist?list=PLdmC1VwRj068TssA-kX1D...
Some of these levels will take a LOT of retries to do. Most of the time you will be doing well and then the game decides to give you completely useless colours... Level 70
I have completed level 70, without taking out more than 2 spheres with my 1st 5 shots (until my combo was max), without missing a shot, without losing my combo, without dropping any pieces that didn't give points, and I still didn't have enough points for 3 stars.Level 70 is NOT possible without paying..
I've added the video of me getting max points to the playlist above.
I brought the cheapest bundle of gems (320) which cost £2.39, I then brought a double points boost (160 gems) and completed level 70 on 3 stars. This left me with 160 gems. Level 74
is hard mainly because there are very few shots to spare. I got 3 stars many times but ran out of shots at the end. Concentrate on taking the clouds out to make everything drop whilst keeping your combo at max.
Rather than keep trying to do it with no boosts, I figured I may as well make it easier and use my unused gems for the game completion. (I didn't record 74 as I used a boost, but I could make a video of a method to get to the top if needed).
I kept playing level 74 until I almost had 3 stars and could finish the level within 5 shots after running out. I ran out of shots then purchased 5 more for 120 gems, I then completed the level on 3 stars with those 5 shots. This left me with 40 unusable gems.
It cost me £2.39 to finish which isn't too bad.
Hope these videos help some of you out, even if it just shows that most of them ARE possible without paying.
I didn't do the 1st world as I got 3 stars on most of them 1st try, so it seemed a bit pointless.