All of the enemies in the level just swarm your position so that you're just hitting mobs until they're gone. You can't even move until you've killed everything. Then you've just got an empty stage to go through until you get to the boss, which is fine since they're short stages. It's obviously designed with this in mind, but it's just button mashing. Hit attack until everything's destroyed. It's basically a step up from an idle clicker. In fact, if you tied attack to the left click, I could just turn on my mouse clicker and forget about it.
It's a very pretty game. Nice sounds and music.