This reminds me of Dungeon Raid which is one of my favourite mobile games ever.
Pretty fun gameplay, although I feel like there's a lack of feedback in this game, and dying seems all too sudden. Understand that due to the tight gameplay period (30seconds) you don't want too many animations to occur but at least some feedback in terms of damage on health like in Dungeon Raid would be useful. Also rather than numbers, having things as a bar would give a quicker indication of how much health / time you have left, as the serif font is pretty but gets in the way of readability (which is crucial in a quick game like this).
The instructions aren't that clear as well, as it seems that stuff that are of the same kind gets removed, rather than all adjacent tiles.
I like the color scheme, the version I played (web game) didn't have sounds though.