I couldn't play it. (iPhone only here), but I watched the video. Seemed like it could use trail-effects for thrown numbers and glows for buffs. I couldn't really get a sense of the selection menu and how stuff worked from just the video, but if you don't already, you could have certain numbers set off super attacks, healing, etc., or create some sort of chaining mechanic like each number thrown does more damage if the previous number's final digit matches this number's. I'm sorry I'm not more helpful.