hi this is a comment for mana match but no comment section on it.
anyway have u thought of making the pieces get replaced from all 4 sides not just the top? a game mechanic i've only seen on 'jewel road'
it was great but finished long ago. basically the match position determines which side the new pieces enter from.
as for extra challenges to game, there are endless ideas but i really like that multi-angle style, cheers.