White to mate in 11!

This is one variation, but whatever moves black chooses, it ends in mate, in eleven or less.

I don't have the time at the moment to find the variations exactly, but first impression is white could have mated faster, or, if not, black made bad moves and could have avoided mate altogether.

Mate is unavoidable! Whatever black does in mate in 11 or less!

Very nice indeed! Got  the first four moves and then got a bit lost in the ozone. Thanks