In order to get this achievement, you need to complete level 12-7. That means you have to beat all 11 levels before it, and then beat in the same playthrough the 7 sections of the 12th level, which is HARD. There´s some tips to make this easier, though.
First, this game seems to track how much have you played, so you get worse balls positions the more you play. That means if you have already 24h achievement and not this, you will probably have messed ball placement too commonly. Last update seems to make the game even harder, so my first advice would be disconnecting from Live, clearing your cache, disconnect the internet cable, start the game with another profile, start a new game, change to your main profile offline, and keep playing after that. You won´t get annoying people connecting messages too, so I would recommend it. But don´t think this makes the game a lot easier, you will just notice better ball placement (and not always). The speed, the random and the luck will be still the same. You can get the time stamp too if you want, by saving the game, going live, update, and reload your previous playthrough.
Next, the key for surviving in this levels is that there´s two ways of playing. Some levels requires a certain way, some others requires another one. You must practice all 7 levels and you have to practice both ways to be able to get the achievement without relying only on luck. Basically they are:
* Fast play. Never stop to think. Never stop to make a combo or a chain unless it´s darn good or unless you will surely get a nice powerup or coin that could be essential. Just shoot the ball you get to the nearest best place you can see in less than a second, even if there´s just one ball of the same color. I repeat: don´t fuc*ing stop. That´s the key. If you see an easy combo, coin or powerup, try to remember it and keep shooting at high speed until you get the needed ball.
There´s many reasons over this:
1) You are clearing more balls in the same time, even if you have good planning at it.
2) You won´t rely on luck so much to get powerups, as you will change a lot more times the ball color per powerup appearance.
3) The entire chain will get slowed everytime you get 3 or more balls of the same color, even if it´s just an instant.
4) If you manage to get the sharp shoot powerup, you will clear balls at higher rate than the chain speed.
5) You will get better reflexes after some practice, so you can then learn to combo/chain better when you need the other way.
Problems you will encounter:
1) You will miss more shoots overall.
2) You will miss many chains/coins/combos/powerups chances.
3) If you just keep making plain 3 ball hits, the entire chain will probably get closer to the end.
* Chaining: The opposite way. Try to shoot at the highest rate possible for you, but stop everytime you can´t make a 3 ball hit. You focus on getting a huge chain, so the level ends darn quick. You try to get every gap and coin you can. If you end up with a ball that you can´t place on a 3 ball hit, and you can´t just wait for new balls because your entire field is filled, throw it to the best place you can find and start the technique over or switch to the other way.
1) The levels will end fastly.
2) You will get a lot points fastly.
3) You won´t miss as many chances unless you are too slow.
4) You won´t be playing the level for too long, so you won´t be as stressed as in the other way.
1) You will be relying a lot more on luck, so if you don´t get good ball placement or wrong colors you are screwed.
2) You won´t get powerups as easy, because you will have less ball colors per powerup appearance.
3) Waiting too much will make the level unbeatable.
4) You will feel the game is cheating to you, as you will be waiting for a chance instead trying to get the best placement without thinking.
5) The entire ball chain will go insanely fast, as you will get high chains and cool gaps, which speeds a lot the game.
I will now list all 7 levels, some tips about them, and which way of play you should use for beating it:
12-1 - The triangle shape
This level will start being rather annoying, but it´s one of the easiest on the pack. The entire chain is short, so the balls can fastly get to the end, although they slow down a lot if they are reaching it. Corners of the triangle are a big no-no, don´t ever shoot a ball on them. Coins are easy to get, so try to get them if you have a chance. Managing a gap in the down section can do wonders too.
Way of playing: Fast. As the level is short and the balls can fastly recover from a huge chain, you must be as fast as you can. Keep shooting the balls on the best placement you can find and you will beat it at least 75% of the times. If you fail, start 12-1 over, as you should beat it with all your lives.
12-2 - Far away spiral
This level can get annoying after you master 12-1, as the entire ball chain is far away from you (unlike 12-1), so you will miss more shoots until you master the level. Coins are harder to get, although the left one can be an easy pick when there´s too many balls of the same colors appearing from the left. Gaps are easier to get than in 12-1, but the chain will be a little faster near the end, so you must play really fast if the balls get there.
Way of playing: Fast. Chaining can do wonders in this level, but I tend to have bad luck on the ball placement more often on this level, and the entire chain slows down when the balls are near the end, so playing fast is the higher success method. Try to get some gaps while doing the level fast, and focus on powerups if the balls are reaching the end. If you are fast, you can beat the level even having the chain reaching the end.
12-3 - Annoying Square
This level is either too easy or too hard. It works that way because if you get a good gap at the top, you can make a lot of gaps and chaining, and if you get a good gap on the right you can get some easy coins. On the other hand, the level is short and the balls are faster, so if the chain gets near the end, you are dead in most of the playthroughs. The first 10 seconds are vital in this level, if you screw them you will probably lose. You best hope is to end the level quickly by building a nice chain and getting gaps and coins, but sometimes is just impossible due to ball placement. Don´t shoot on corners ever, and be careful when shooting, as the angle can really screw your shot.
Way of playing: Chaining. Playing fast alone won´t save you on this level, it´s made for huge gap chains and getting coins. If you get bad luck from the beginning, swap to the fast method, but try to use the chaining method as much as you can. If you don´t get too bad luck, the level will end quickly (be careful on the remaining balls, as they are even trickier than in previous levels). I think it´s one of the levels where you need to rely more on luck, as a bad ball placement can be hell on this level.
12-4 - The "you won´t be able to shoot at most of the balls" level
This level can get annoying, although personally it´s usually easy, as it has good ball placement most of the times. In this level, you can´t shoot well enough to the balls reaching the end, so you must focus on the chain not getting too far away. Coins are easy in this level, gaps aren´t, so try to get a coin everytime you have a chance. Most balls will be unreachable at times, so you won´t be able to get powerups as often as previous levels. Once you get to the end of the level, when there´s just some balls left, focus on powerups though. Balls reaching the end usually ends on a life lost.
Way of playing: Fast. You can do chaining if you want, as the level can end quickly and there´s better ball placement, but you will be screwed if the chain advances too much. There´s usually just three easy spots to shoot balls: the top left corner, the right way, and the bottom way. It´s better to focus on the right and bottom ones, as you can get easy coins there, but shoot at the top-left corner everytime you can´t shoot to either ways. If you are fast, the chain won´t get to the end in most of the playthroughs.
12-5 - The two chains level
This level is tricky for many people, but it´s actually one of the easiests of the group. Yeah, you have two chains at different speeds to care for, but you also get double the powerups, and it´s an easy gapping level too. I think most players rely on speed, which works in previous levels, but here, the key is chaining. Wait for every shoot, get sure you won´t fail it, and focus on getting powerups. The level will end quickly, the balls won´t reach the end at all, and you will have a powerup help nearly everytime. Don´t try to get coins unless they are too easy to get.
Way of playing: Chaining. As mentioned above, you will rarely end with a ball that can´t be placed without chaining it, and you will have gaps and powerups nearly always available. Exploit them. That´s the key of this level. The reverse powerup tends to be just a small help on other levels, but it´s the key powerup on this level, as you reverse both chains, so get it everytime you see it. The chains slow down a lot when reaching the end, so be careful if you reach that situation, and you will maybe success at it.
12-6 - Insanely fast level
This level has really good ball placement (maybe the best of all the levels), and you can always reach the new balls to get new colors, but it can be the level where you lose all your lives easily. What´s the reason behind that? The level is insanely fast (fastest level in the game), the end of the chain is unreachable at most of the game (even when finishing) and the balls don´t slow down when reaching it!! That means if 3 different colored balls are near the end, you will die, even if you have completed the level and there´s only 5 balls left in the entire level. You won´t make it. As the level is so fast, you won´t be able to get powerups as easy (you will rarely spot them at all, as the chain is too fast). That means the key strategy is slowing the entire chain everytime you can!! The slow powerup is the key powerup on this level, exploit it everytime you can.
Way of playing: Fast/Chaining. What am I talking about? Play the level in the Fast way, but focusing a bit more on chaining. You must keep destroying balls at every time, as two seconds could mean death. Failing a shoot usually means death too. So you have to keep throwing the balls at big clusters of balls of the same color, and get the coin or gap behind them if you can. If you keep destroying balls, the chain won´t be able to gain max speed, and as the ball placement is really good, you will be able to get easy shots nearly everytime. Just don´t screw up, really. At the end of the level, pray for slow down or reverse powerups, as if you are left with too different colored balls, you could lose the entire level easily.
12-7 - Just ball placement luck level
This is the last level of the pack, and it can actually be easier than 12-3, 12-4 or 12-6... As long as you have luck. You won´t be able to reach the balls that are reaching the end, just the newer ones that appear on the center, so if you have luck with those ball placement and the powerups, you will end the level easily. If you keep getting bad ball colors, bad ball placement, and no powerups, you will fail easily. The last tricky thing of the level is that you have all the balls near you while playing the level, but after completing it, the remaining ones will be really far away, so it´s really easy to miss the last shots and die because that. That´s the reason you should try to get the sharp shoot powerup in this level, it will make the last balls a lot easier.
Way of playing: Chaining. You need to keep the chain to succesfully complete this level, and it shouldn´t be too hard, as there´s new balls coming near you everytime. The level isn´t too fast either (although it doesn´t slow down at the end), so doing a huge chain will end the level quickly. The tricky part will be the remaining balls, so you better have gotten the shar shoot powerup by then. All the other powerups do wonders too on this level.
You start at 12-1 with 3 lives, and if you are reaching 12-7 you will surely have reached 100.000 points by then, so you have 5 lives to complete all 7 levels. After beating them, you will get to 13-1, the last level in the entire game, which unlocks yet another achievement. This last level isn´t hard, but it´s tricky and you will probably fail it at the first tries, so exit saving the game, and practice the level on Gauntlet. Don´t be stupid to get there just to fail because you don´t have enough practice, as you will have to start over from 12-1 (and you will hate that). Don´t be fooled by this achievement ratio, it´s hard and you need both luck and skill. So if you are lucky and skillfull to get there, try not to screw up.
If you have trouble on any level or any questions about this tips, please, ask them so I can help you. I´ve played too many hours this levels to learn how to play them, so maybe I can get the clue you need for completing them. Good luck on it!