Rollaround

In Rollaround you roll around (surprise) 20 levels, in a game which comes across as a more cerebral version of Marble Madness. The twenty levels each feature 9 screens worth of squares, with no scrolling across them as such. On each level you are set a target number of crosses of each colour to collect, with less and less leeway as to how many of the different ones are required as the game goes on...