Here is a video of me getting the achievement, the winning run starts at 3:25:
The Dreamcatcher achievement. There is no easy way to get this achievement. I will provide you with everything I know and I wish you luck on this achievement.
If you are interested in it, be prepared to spend hours trying to get it! I personally spent about 15 hours. My scores improved from 35 on the first day, to 44, then 47, 49 (four times in a few hours) and finally topped it off with a 50.
First of all, to get this achievement you need to play the battle mode by going to Multiplayer and then choosing Private Match or Local Match. It doesn't matter which as long as you set it so nobody else can join. You need to make sure that the bots are on "Nightmare" difficulty, and that you are playing in the Battle gamemode.
These are the settings I used for the achievement, and the reasoning behind it:
Not round based (Triplets first to 50) -- I don't believe I can survive long enough versus 3 bots, in a first to 3. If my board gets wiped I still have a chance to go for the win.
Use Same Boards -- My logic for this is that the bots will do very similar in performance, and while yes it could be an easy board you still have the opportunity to do better than them. I dislike not using the same boards because not only do you need to have a good board, you also have to bank on the fact that all the bots have a bad board. Very small chance of that happening. Then, on top of that, you still need to do it mistake-free...
Rubberbanding -- I still don't think that I could ever be faster than the bots 100% of the time. I'm pretty good at the opening puzzle and can be faster than them there, but the second or third one gets me all the time. That is why, when the bots are in the lead, they will spend an extra few seconds being wiped, while I hardly will ever get the lead, so the rubberbanding will not affect me.
Handicap set to 3 -- BUT, I don't think this made a difference, I was hoping it would handicap the AIs though :P. I think this is broken with all these settings on, because in other cases you get green blocks right away. If you noticed, I didn't get any. Maybe just the red/yellow/blue blocks were just placed harder?
In the video you will notice that the winning run starts at 3:25, the runs before show you the failed attempts leading up to to getting the achievement. These are important because you need to know when to giveup a run so you don't waste your time. At the time of this writing I'm #1 on the TrueAchievements leaderboard for games played and I believe that me returning to the lobby many many times contributed to this. You need to make sure you get at least 15 on your first wipe, and 30 on your second wipe, or else you will have a much bigger mountain to climb than usual.
What you need for this achievement: Lots of practice, and very much fortune, and perseverance! No, seriously. It doesn't matter how perfect your run is, the bot can still beat you. I had it happen the other day, where the bot didn't wipe at all but got 50. You just need the right circumstances to fall into place. You need to believe in yourself! If you think you can do it, you will play better!
What you don't need for this achievement: A perfect run. If you noticed, I made two mistakes on my winning run. You do need to be able to recover from those mistakes pretty quickly though.
Now for the tips:
1. First of all, you need to mash the A button, furiously but with care! If you don't go fast here, then you have no hope of getting the achievement. There were like two hours where I became lethargic and slowed down (but still made the right decisions) and I was nowhere near 50.
2. There is a bit of an exploit that I used that goes with the above tip. If you mash the A button on a group of 3, you get the color pretty quickly. But if you press the A button over a color block that is not a legal move for the first time, it won't take that block. So I was ready to spam the A button and I even pressed it on blocks that I had no intention of picking up just so I can "keep the rhythm going"
3. Also going with the top two, you need to mash the A button even before the puzzle begins. You need to do this the second wipe, and the third wipe. YOU NEED TO BE READY TO GO! If you don't the board will go down so fast after the wipes and you won't even be able to get 5 triplets. If you've beaten Tetris Splash before, this game mode is very similar to how it is played.
4. Another exploit I know, which I think I used on the winning run, is: You are actually allowed to mess up twice before the board moves down for a non-legal move! This means, if you make a group of two, accidentally grab another color, you can then grab a third color or go back to the first color and it will only count as one mistake! It could be very useful to remove blocks.
5. When in doubt, spam out! If I know I'm about to lose or I am out of moves, I spam the A button on a column that has a lot of the same blocks. This gives me an extra one or two triplets which can help in the long run. I do this pretty often on my third puzzle as well to hope it gets me to 50.
6. Instead of looking for groups of 3's. You need to learn to identify 6's and 9's. You need to be ready to grab them all at once. You are pretty much counting in your head while you play and look for more moves. The game has a built in counter that gives you a check mark whenever you match a group of three, and provides a number for how many triplets you scored...but I didn't use those. I didn't want my eyes fixed on that area, only on the blocks themselves.
7. Probably not that much of a tip but it helped me...mute the audio! It gets annoying after awhile, and can startle you at the worst times! Silence helped me stay focused.
8. When your board gets wiped for the first time, take a quick glance at everyone's scores and how their boards are. If there is a bot at ~25 or so and hasn't wiped yet, you might as well restart.
9. The better that you do, the worse the bots do. You'll notice that if all the bots wipe at the same time, the board stops moving. The same thing happens the other way around. By continuing to get triplets the bot's boards will wipe faster.
10. The third puzzle (second wipe) is the most important one! You don't have to be in the lead at all as long as you win at the end. Be prepared to go full speed on that. I think it might even help to not be as fast on the first two, so that rubberbanding comes into play.
I may add some more tips later. Good Luck to you all.
If you have any questions or need me to be clearer please let me know!
EDIT: Fixed tip #2