Finished this in 12 seconds. Is this a record?!

Very good grid, easy and fun.

very good.
i solved it quickly but was not right about the metals so it still had an edge of extra learning for me! ^_^

Nice one. Very fair

nice puzzle

2/4 right for me, a good grid though

Well done you got me going down a red herring group of bus types

Metals group - tried twice to name connection - firstly "metallic elements" and secondly (after repeating the puzzle) "heavy metals" - both incorrect, so checked answer (toxic metals). Heavy is equivalent to toxic, and in addition the more scientifically correct (and certainly more used) term, therefore should be an accepted answer.

the toxic metals are also elements.

'Toxic Metals' is a pretty poor key word set. They all belong to several larger groups "chemical elements" is perfectly valid

It's good but some of the key words have been poorly chosen.

Loved it :) very nice!

Add planets and candy to the key words.