I like the that you have to move around a lot in this game it cuts the boring waiting part of tower defense games , I think there could be a bit more strategy involved in this game , because as it is now the best strategy is to collect as many animals as you are able to until you place just as many as needed on a part on the map where the paths of the enemies cross or directly before the egg .
A possible solution for this would be to carry only one of each animal at a time and design the map so that there is no best position for placing your animals , this could be maybe made more interesting by letting you upgrade the animals .
But anyways this is by no means bad game I enjoyed it until the end , the music is fantastic , gameplay is fast paced and overall well polished . keep up the great work