BTW – Puzzle Maze review: A mind workout game with minimal design & zero learning curve

This free puzzle game is a real workout for the mind! It has a minimalist design and zero learning curve. All you need to do is drag a line through a field while collecting all the circles. The twist is that circles are two different colours (black or white) and only one is visible at a time. You can switch the level colours before you start but you must collect all circles and exit to complete the level.