Fun game, except the controls need to be more responsive. Nothing hurts a good game more than the character not doing what you tell it to do with no reason. For example, running across a moving platform and then hitting the jump button but instead just falling off the edge.
This game has a lot of great underlying elements. The UI is accessible. The pace is good, so no need for a speed control. The upgrades are attainable, but takes some repeating of levels to unlock them all. And the mechanics are minimally complicated, making it easy to understand how effective your units will be.