Kirby's Dreamland - Amazing game. It got me into the franchise. I was in 5th grade I think.
Kirby's Adventure - HOLY FUCKING SHIT!!!! Awesome! GBA remake = awesome in my pants.
Kirby's Dreamland 2 - Looking back, I'm kinda disappointed with this one. These were less powers despite the animal friends, and the level design was pretty bland. The rainbow drops were hard as hell to fine though, and the last boss was pretty tough.
Kirby's Pinball - Cool pinball game. Nothing special, but damn fun.
Kirby's Block Ball - Awesome twist on a classic game.
Kirby's Dream Course - I find this game incredibly fun yet hard. I never got past the first world. I solute anyone who can bet this game.
Kirby's Super Star - A gift from heaven, and the DS remake is a gift from heaven in my pants.
Kirby's Star Stacker - Very cool puzzle game. I'm not counting the Puyo Puyo reskin because... it's a reskin.
Kirby's Dreamland 3 - Very underrated IMO. Much better than Kirby's Dreamland 2. While it's more of the same, the levels are just more fun. The new friends and power are awesome.
Kirby 64 - Another underrated game. Combining powers and finding all the different possibilities alone was fun. The powers were very creative too. Darth Maul Kirby. Kirby CAN'T FLY in this game. At least not forever. His flight is limited in this game so it's a bit trickier. Of course, it's not that hard either. The mini-games are incredibly fun too. I spent hours playing the block smash game.
Kirby's Tilt and Tumble - Never played it.
Kirby's Air Ride - Never played it.
Kirby's Amazing Mirror - Here come Capcom to crap up another Nintendo franchise. Boring Metroidvania clone with a horrible map and stupid gimmick. The level design's ok, but there's very little to discover. Kirby Super Star's Great Cave Offensive was much shorter, yet packed with 3x as much hidden treasure to discover. The awful map just kills the exploration. The half-assed powers also sucked. They wanted to make it like KSS, but didn't go all out with it.
Kirby's Squeak Squad - Crapcom... need I say more?
Kirby's Cursed Canvas - I got it at launch, and at first, I didn't know how I feel about it. Getting used to the controls took longer than I thought. I stopped for a while to play other games and had to relearn the controls again. Once I mastered it, IT'S FUCKING AWESOME!