The copy on the back of the Think! inlay says:
So you can think, but can you THINK, SPEED THINK or even BLITZ THINK? Here's your chance to prove it.
Think! was released in a standard cassette case. One of the screenshot's on the back shows the game saying it was Colin's turn, referring to Colin Fuidge, who worked at Firebird on the budget range.
For some reason, Think! lost it's exclamation mark on the cassette label for this budget re-release.