It's a good little time killer! It's not anymore complex than it needs to be, and it's simple enough that anybody can sit down and understand what's going on enough to have loads of fun with it. The art is super charming, and all the colors pop really well, which is a huge plus. The option for keyboard control is great, especially for poor suckers without a decent mouse. If I had to offer criticism, I'd say the difficulty never really picked up like I expected it to, and after a while the invasion segments started to feel like padding more than anything else.
Can't recommend enough, would make a good mobile game for sure. Ruffle is looking more and more viable to me, and I'm glad I was wrong about my initial thoughts on it!