Well, gotta come out of the woodwork. I actually like this game. Amusingly, it took me having played Guilty Gear X to appreciate Ragnagard.
As EvilMike said, it's an aerial battle game. And there are similar concepts in both.
There's air dashing which I initially thought was implemented well for the first time in Guilty Gear X. It's done well in Ragnagard too. I wouldn't be surprised if the Sammy developers took much from the Ragnagard game engine. You can air dash immediately after jumping attacks and vice versa.
The ground dashing is very useful too and most moves can be performed during the air dash or ground dash as like they were on the ground.
There's a air combo like initiator (like in GGX) where you jump and press AB then carry on a combo.
The Power Meter system is very novel. A little difficult to put clearly in words and you have to try it yourself to understand fully. There are 4 essences; Fire, Earth, Water, Air. Each character has 2. Press ABC to charge up the first essence and BCD to charge the second. Upon charging up, the air fills with interference from the respective essence and (I think) if you happen to be in a position of where the essence discharges, e.g. tiny flaming eruptions on the ground or lightning bolts, etc., you gain a power stock of that essence. Needless to say when both characters are charged up, a lot happens on the screen.
The point of having 2 kinds of power is the DMs. You need the particular essence stock to perform the DM. I took me some time to figure out and consistently execute Susano's Fire DM but once I did, I kept doing it coz' it really looks cool. mr_t Hard to describe and best if you see it for yourself. If close enough, all blasts will hit and the last two beams will hit as the opponent is launched into the air. Sweet.
The only faq on gamefaqs (by Bun) lists that the SDM can only be performed by having 3 power stocks and red life. I found this not to be the case thankfully, you can do it whenever you have red life. However, and I find this a little strange, if you happen to have 3 power stocks when you perform the SDM, they will be drained. I'll probably experiment more to see if the SDM can be performed with non-red life and 3 stocks, or whether it does more damage with the 3 stocks.
Other characters' specials and DMs are quite spectacular too. You will find that many ideas have been borrowed by Guilty Gear X as well as character designs.
The combo system is existent and quite alright.
I think the main thing that detracts from the game is the range of the normal punches and kicks. You have to be really close to combo.
The pre-rendered polygonal graphics are quite interesting and different from the usual fare. A much better effort went in to this game than Brikinger, which I thought was a pile of turd. Ragnagard was made by Saurus and System Vision.
Point to note, don't get this game based on my taste, I got an original butchered MVS cart cheap for $5.99.