I have been a fan of shmups for about 22 years now. The very first shoot'em'up I ever got my hands on was R-Type on the GameBoy. The first bullet hell I ever got into was ESPGaluda II on a friends PC running it through his MAME emulator. Well, needless to say, I couldn't be happier as an iOS gamer. The genre is one that translates INCREDIBLY WELL over to the touchscreen, and if the developer is willing to try something a little different, they can wind up with a control scheme that allows for deep gameplay without having to have a bunch of buttons all over the bottom of the screen, usually only a big deal if you're trying to play for a high-score. Ito Masayuki's first hit, .Decluster: Into The Bullet Hell is a masterpiece. The very first time I played it reminded me of Space Invaders Infinity Gene and Danmaku Unlmited 2. The later in the scoring mechanics, as you will be grazing through quite a bit of bullet curtains in order to maximize your star count/multiplier. Infinity Gene simply because of the cosmetics of the game.
Building on that, .Decluster Zero is more of a .Decluster Remixed. You'll start on Stage 5 and work your way backwards to Stage 1 (and then 0!), with new mechanics, bullet patterns, enemies, and more. If you're a fan of Cave, think of this as the Black Label version of .Decluster. Are they both worth owning? Most definitely. Should you buy Zero first... I wouldn't. Now that I've gotten accustomed to the new mechanics and everything - I keep wishing they were added to the original. Though, that doesn't take away from the original at all. Because of the mechanics, the two play out fairly differently when taking on scoring runs. Having leaderboards for every single stage (and now an added 'replay' button in the pause menu!!!), some pretty challenging achievements and Everyplay integration all makes for some pretty intense gameplay. I dunno what it is about knowing that others are going to watch and judge your game adds another level of stress to the already assertive nature of the genre.
Now, granted I've only cleared Normal mode and haven't even unlocked half of Hard, or started on Heaven difficulty, but after clearing Normal, I've come to a realization. .Decluster Zero: Bullet Nocturne is easily in the top 2 best bullethell titles in the AppStore. Yes, I own Danmaku Unlimited (1&2), every iOS Cave game, Shogun, rRootage, Sine Mora, Phoenix, ect... and I just can not get over how insanely fantastic the .Decluster duo is. Especially considering it all came from one man! If you're a fan of the genre, or just curious as to what the genre is like... snag this game. Snag it now... you will definitely NOT regret it.
Oh yeah... MFi controls work FLAWLESSLY. They are also customizable with button assignments!!! Frick'n AWESOME!!!