Nice concept of absorbing only the right circles which have numbers lower than yours! However, while playing sometimes I would just be stuck with a number lower than all the other surrounding numbers and then I would need to wait!
I would suggest making more things happen and make more numbers that you can absorb appear more frequently and making it more urgent to make sure the player pays attention! Also you can make it so they have to carefully make a path to get to the lower numbers when bigger numbers are nearby because you can just click on the lower numbers to get them!