A portion of Nintendolife's review:

there are plenty of exercises across ten sections to keep pupils busy for a long time. The bonus game reward for those gold stars, meanwhile, is a modest, mediocre effort. Once again it’s a grid-based affair, where one line of coloured blocks is complemented by additional lines at short intervals. The only requirement is to look for groups of three or more blocks of the same colour that are together, and tap the group to clear them away. Tapping the blocks to clear lines is all there is to do, meaning that it serves as more of an eye test than a genuine puzzle game.

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Source: Nintendolife