Don't give up!!! Its actually becomes much easier if you focus on getting rid of the slime dots a section at a time (left, bottom, and right sections).
First when you start the level and before you make any moves, see if you can make a square right away. If not, exit the level, you won't lose a heart as long as you didn't make any moves. Then select the level again. It helps get things started to be able to make squares right away. Keep making squares until you start seeing a pattern of color dots that will allow you to remove all the slime dots in one of the sections (left, right or bottom). Most of the time the bottom sections will be the one where you can remove all the slime dots first since if you making squares its quite easy to have that entire row be one color. If you lucky you can have that section slime free by just making squares, but most likely you will not be able to remove the slim dots on the left or right section by just making squares.
Again don't bother removing slime dots in a section unless you can remove them all entirely, because if you are just left with even one they will quickly spread and you have to start all over again. It better to just use your moves to keep making squares until the right combination of colored dots present themselves in each section for you to remove the slime dots.

The key is to not get caught up in making squares in the middle and get distracted from getting rid of the slimed dots on the left, right and bottom sections. When forming squares make sure to check which sections you can get rid of the slim dots easily first. If you don't have the right combinations of dots in each section to get rid of the all the slime just move on to keep forming squares in the middle until you do. There almost no point in trying if you end up with one slimed dot left still in that section, as you will have to start the process all over again since they quickly spread back new again. Just focus on getting rid of the slime dots a section at a time.

This is probably the most difficult level of the new releases.

Similar to level 380, this level is much easier if you can create a square with colorless dots. This will remove all the blocks.

Take out the 4 Nesting Dots at the bottom as quickly as possible as this would make the level a lot easier afterward.

I was stuck on this level for awhile. The key to beating this level is to create a square not with a single color, but with colorless/empty circles. This will break all the blocks and get rid of all the fires as well.

If you try to beat this level the conventional way of making color squares would be very difficult and you would need extreme luck.

Yes I was able to beat this level without buying extra moves and powerups, but it was really hard and I honestly started to think it was impossible. It took me little less than a week and it took all my moves.

In terms of tips, do not get rid of the blue monsters. They are the key to being able to create blue squares so frequently. I know some people have said that they need to be removed as soon as possible, but that doesn't make sense since they create blue dots which is the hardest thing to get.

First thing to do is if possible is to try and get the green dots. In the process of doing that if there is an opportunity to create blue squares than do that right away. Moves are limited so create blue squares when they first appear, ignore the green dots early in the game if you have to. Be patient as you can not waste any moves. Make green and blue squares as soon as you are able.

Once you obtain or are close to getting 40 green dots, than its time to focus on blue dots. Create squares with other colors such as yellow and purple to quickly cycel back blue dots.

The key getting enough blue dots are the two monsters. At the start of the game there is a monster at the top and a monster at the bottom. If things are going correctly and you are creating squares as a good rate than both monsters should be close to each other on the bottom. This is key since by having two monsters close to each other at the bottom they will be able to create blue dots around each other and makes it easier to create blue squares. Just make sure you keeping clearing the other colors with squares to cycle the blue dots back.

It going to take some luck and the right dots are going to need to fall you way, but it is possible. Just don't waste any moves.