Well, that would be a good reason why you haven't cleared a Lunatic yet. The only advice I can offer is to try and play an hour every day. If you don't feel like doing that then you shouldn't worry too much about not having cleared a Lunatic yet. That's fine. The important thing is to play something that entertains and challenges you. Not just play something that's named Lunatic even if that would make it sound cooler. There isn't any rush, you can take things at your own pace. You'll get there one day. Given that you don't quit of course.
I do have a recommendation for you though. Try timing out difficult spells in IN. Spell practice lets you instantly access hard attacks that are fun without forcing you to play through soulcrushingly dull stages every time. Playing through stages is not only boring, it won't help you grow skills either since most of them are so trivial and fixed. A random and hard bullet pattern though will help you get better at dodging and to be able to instantly access it is an effective skill-grind or so I've found it to be. Make use of it.
Just too bad the feature is missing from anything else but TD though. SA and UFO would've been twice as awesome if you could just skip the bad parts of the game. IN will be hard enough for you though so give that a shot. Time out Asteroid Belt, Brilliant Dragon Bullet and Apollo 13 for example.
