Boosters

Every level gives you four boosters. None of them is ever needed: every level has been cleared without them, and each level guide shows a solution that uses none. But they can rescue a run, and each one you use costs one of the three stars.

Extra Slot (1 per level)

Adds a sixth slot to the nest for the rest of the level. It is the gentlest fix and the best choice when you are one slot short, for example when a chained pair arrives and only one slot is free.

Grab (2 per level)

Lets you take a box from the second or third row of a column instead of the front. Use it to fetch a color that is exposed right now but stuck behind a box you don't want. It cannot take chained or locked boxes.

Machine Gun (2 per level)

Blasts any 3×3 area of the picture. It breaks ordinary blocks outright, takes several bites off number blocks, chips at spider webs and shatters ice. Aim it at whatever is covering the colors your slots are waiting for.

UFO (1 per level)

Pick a slot, and the UFO lifts blocks of that box's color straight out of the picture, wherever they are, one for every ant the box still holds. It is the strongest fix for a jam: the box empties and leaves, and the holes it leaves often uncover the next layer.

Stars

Clear a level without boosters for three stars, with one booster for two, and with more for one. When the nest jams, the lose screen offers the boosters that would actually help.