Now, I don't know if this particular secret location is present on versions of Zool outside the UK, but it's worth a go...
1. On world 1.3 (Sweet World), continue to the end of the level and defeat the Humbugger.
2. INSTEAD OF MOVING RIGHT, go back to the point where there are four buttons marked "HIT". Then... er... hit them (they'll turn yellow).
3. Continue left until you reach the large drop.
4. Fall off this and wait by the right hand side of the drop until the counter falls below 100 (I think that bit's right).
5. Punch away at the wall on your right, and it should reveal a mass of sweets arranged in the word "GAMESMASTER" (a popular computer games programme on British TV), and there are a couple of extra lives and time bonuses - and another exit!
Like I said, this might not be on non-UK versions, but there's no harm in trying...
