Very neat mechanic, but having the non-selected slime slide all over the place makes it very hard to control. Maybe locking the non-selected slime in place and having the spring effects only affect the currently selected one might help. Nice work :)
I actually do have a similar mechanic in place although looking back on it maybe I haven't mentioned it so clearly :). As it says on the title screen, you can stick the active slime by using shift. Have you noticed this or? Anyways thank you for your feeback!