So this is one of the best shoot 'em ups I've ever played. Seriously. I'll give you my credentials, I've been playing since Gradius, Raiden, etc, I import Japanese shoot 'em ups like Ibara/Espgaluda/other Cave game, blah blah. I'm a huge fan of the genre. But this one is simply one of the best, because even after all these years, Syder Arcade took a classic genre and breathed new life into it.
Seriously, if you've ever played Gradius and wanted to just turn around and shoot that guy that just
made it by you... do it! In Syder Arcade, you can literally turn your ship around in the other direction at will. Better yet, you can actually travel backwards through a level by doing this, in case you... missed a powerup, or an enemy, or whatever. There's even a defense level where you have to survive for a certain amount of time protecting a huge allied battleship (which doesn't need an egregious amount of protecting), and you will travel back and forth through the area quite a few times gunning down all the ships that appear. You can also stop moving altogether; the screen doesn't scroll without your permission. It's like... you're actually flying your own spacecraft. It's crazy.
Syder Arcade also does something else I haven't ever seen a shoot 'em up focus on: melee combat. I know, the idea is ridiculous. You're in a spacecraft, for crying out loud! But in Syder Arcade (like in many good shoot 'em ups), you have your primary weapon, and your secondary weapon (the latter of which needs to be charged in various ways). Though each of the four selectable ships have different secondary weapons, all of them put a shield around your ship for 2 or 3 seconds. During this time, you can literally just ram the hell out of enemy spacecraft. There are even bonuses for doing it! It is GREAT! You can also absorb bullets this way, for which there are also bonuses. And one of the best parts: you have a health bar. One mistake isn't necessarily the whole game!
Seriously, this game is worth playing, even for shoot 'em up fans that think they have seen it all. What I really like, too, is that it's not exactly a "bullet hell" game. I know those are really popular, like Cave games, Touhou, etc... and I like them, but every once in a while it's nice to focus more on blowing stuff up than memorizing bullet patterns and stuff. There are still plenty of bullets to dodge in Syder Arcade though, and the game won't go down without a fight on "Pure" difficulty.
The one thing I have to warn about: currently, Survival is quite buggy. None of the achievements for Survival unlock (at least, they didn't for me after 3 hours of trying and some top-80 scores). Also, the ice level is totally bugged and will freeze the game, and the juggernaut level also won't end and will just sit until you quit out. This kind of hurts Syder Arcade's replayability, because if it's anything I love about a shoot 'em up, it's a good Survival mode to improve my scores on. But even aside from this, it is so worth playing through this game and seeing what fun things you can do in the genre even after all this time.
Highly, highly recommended, a favorite of mine on all of Steam!