Fact: The day after writing this I got to World 2 for the first time. So there you go.

The enemies aren't random, and you start to anticipate when they'll come. (I used to get the first ten before they even made it onto the screen.) The bosses are hard, but you get to know their tricks – for example, the boss at the end of World 3 always defeated me until I realized I could knock out his guns and then effortlessly glide back and forth between the waves of bullets, picking off his cores. Reaching maximum strength (and not losing it) is of course key. If you don't die by the end of World 1, you'll have almost your maximum firepower, and everything that follows – bosses, waves of enemies – become much easier. But I always got knocked back a bit in World 3. As you say, your finger can get in the way and it's hard to see people who are attacking from behind you.

The revelation in this game (and I know it's not the first to do it) is how well it worked on a touchscreen: instead of making you press a "FIRE" button, it's always shooting. That's so great! Why WOULDN'T you always want to be shooting?

But you know, it can be done. And it only takes about 14 minutes end to end. I'm not a shmup maven but I loved this game and I kept at it until I beat it. Best of all, the game records your high score run and you can watch and admire it anytime!