When you leave a shooter for a while, go play something much harder for a couple of months then come back to the previous game and smash your old score on the first credit like it was nothing.
I hadn't touched Mushihimesama Futari Black Label in a few months. Been playing a lot of Dodonpachi Daioujou lately. Went back to Futari the other day and had my best run yet. Almost 1 cc'd original Black label (died at the final boss). Not a great accomplishment for most but for me it was!
I spent the past few days playing Bakraid's Advanced Course and just now went back to Normal Course for a credit. I killed my old Normal Course score and clipped 30 million for the first time.
Today I am too close to my skill ceiling in shmups (and many other genres) to really feel a "general" skill progress - this could happen before but won't today, only proper learning of the specifics of said game (paths, scoring system...) will really help.
I do think putting a game away for a few days (if not weeks) help most of the time, 'though. If I become too obsessive with a game, I can easily get frustrated with not seeing any improvement.
i never could figure out the arcade version because i'm a derp, so i went to play project on very easy mode because lol
i kept dying to the dumbest things, in just about every stage; didn't get to the loop once
i go back to the arcade version because i got sick of terrible ps emulation (must have keyboard) and i get all the way to stage 5, when i couldn't even get through stage 2 before