The arcade style is fun, but it gets a bit boring having to start from the beginning all the time. I'd like to suggest that an additional campaign mode would be great - it could be just as simple as increasing score targets for each level, but levels are tweaked for what spawns/timing etc. Alternatively it could have specific targets (e.g at least one chain of 10).

Another suggestion is the inclusion of extra life specials. They would give you a chance to continue after sparks crash. You could apply a score penalty every time you use them (e.g -5% of current score, increasing every time you use one 5/10/15%).