Geist is an underrated gem! It actually appeared on one of my earlier "Pick 60" episodes. It's too bad that n-Space folded, even though the quality of their output had waned in later years.
Yes!!! I haven't played Ikaruga in years (my buddy had a copy in high-school). I remember the endless sweet, sweet frustration :D
I picked up reasonably cheap on Steam awhile back on a sale. So if you have PC probably can pick it up there for like 4 or 5 dollars during a sale.
Apparently I gotten worse but the game is all about memorization and quick skills like knowing when to change colors. The more you play usually further you get. However I've had friends that are good at other genres play it and they are terrible. Funny how some people can be good at genres but then you play another genre and they suck. It's like how you are that bad at Smash?