There are certain Shmups on the DC that get a lot of attention and some for very good reason. I wanted to see what people ranked as their favorite shmups so I'm going to do a quick list of my favorites from favorite (1.) to least favorite and give a short description of why I thought certain games deserved the ranking they received. Feel free to do the same in any format that you see fit :D

1. Border Down - Brilliant music, literally my all time favorite game soundtrack. A cool concept, the border system, that can sometimes be frustrating but once mastered it adds limitless potential and depth to the game. A game that is hard to survive but even harder to play for score. A remix mode that changes the enemy designs and patterns across every level and sub-level as well as a lot of difficulty levels. This game is incredible but only if you are really willing to give it the time to grow on you.
2. Psyvariar 2 - The only shmup I haven't reached the (real) final level in and for good reason. It is so intense that it hurts my hand after about 30 minutes of gameplay :D . The game gives you the option to play as a standard Shmup (shoot type) or an even cooler variation (buzz type). The buzz system works so well that it makes the game feel like something other than a shmup, almost like a beautiful dance game or some shit like that. Poetry isn't my thing but this game deserves the attempt!
3. Mars Matrix - A game that can be played in a lot of different ways. Two different ships that each have two different shot types that need to be interchanged constantly for best results and the unique bomb system makes this game a complete blast. The experience system is incredible and the difficulty is top notch.
4. Trizeal - By this point you might be wondering "he's at number 4 and ikaruga hasn't been listed yet?!!?! Will it make the top 5?" to which the answer is No since it is everything that Trizeal is not and everything that makes Trizeal feel incredibly fresh. Trizeal is a shooter, not a bullet hell. The game does not rely on a set "win pattern". There is no one way to play and memorization will only take you so far since (sound the drum roll please) the enemies actually shoot at you! While this was a pretty common feature of early shmups its pretty rare in this day and age and it makes the game so much fun and so difficult despite the relatively small amount of bullets coming at you.
5. Castle Shikigami 2 - Castle Shikigami 2 does not attempt anything new but rather mimics other styles near perfectly to make a crazy ultra game. You have a ton of characters with tons of different moves that have either been done before or have not but almost every character works in almost every situation. There is a buzz system present throughout as well even if it isn't as grandiose as Psyvariar 2. The level design and enemy design help make this game a cut above the rest. I'm going to find a video of the "puzzle-boss" later, it is fucking awesome!

Well, that's it for now but I could easily do a 6-10 and so on, I love my shmups :D