Thank you!
Level 5 is actually a confusing point for many, which unfortunately slipped through playtesting! We definitely need to add more tooltips/hints to it. One of the game mechanics isn't well explained, which leads people to get stuck on the level: If two slimes of different type touch, they will not combine to form a new color! You will only get the stronger type of slime. For example, if a green slime and a blue slime touch, the resulting slime will still be blue, and the green slime will simply disappear! Because of this, you need to be careful not to let slimes of different types touch, otherwise you will end up "losing" a slime and won't have enough to make the purple one.