I was watching a video on Super Mario clones/ripoffs and Giana Sisters came up, which I had no idea started life as a C64 game. It looked pretty lame, but judging by the games here, it seemed like the franchise had come a long way since being accused of a Nintendo ripoff. I was wondering how they are as games and why the second one is far cheaper than the first.

TBH I've never heard of Giana sisters untill now. but to me it looks more like a sonic clone then a SMB clone.
As to the price, that's easy, games develope a fanbase and the more popular a game is the greater it retains it's value, case in point Skyrim, the SE still sells for 20$ for a 6 tear old game that is fairly high, not so popular games the price drops drematicaly as it ages as the developers hope ot make any profit from it.
as to gameplay. well it is not my sort of game, I don't like platformers.... but from the in game footage it looks fairly stable, both the 1st and the second games. over all I'd say it's a personal preference as to the game and how enjoyable it is /can be.

Dunno I'll reserve my decision until the linux version comes to humble bundle, it'll be here in late 2014.

I only played about ...30% of the first?

Would agree it's definitely more in the Sonic vein than SM. That's actually the main reason I didn't go farther - I'm just not particularly good at that particular subgenre. Did okay at Rayman Origins, and absolutely loved Dust: An Elysian Tale and I'd say Giana Sisters is definitely Sonic-er than either of those.

I did quite like the graphics/style, and the game's premise/mechanic is pretty cool. So if you're into that style of action platformer, I think it does a good job at what it is.

I just had trouble with the mechanics of getting past certain combo jump/fly/swap/jump action moves to get over certain hurdles, probably due to it not being my main gaming skillset, and playing KB+M rather than controller.

TLDR: So this may seem a weird upvote, but I quite like the game and recommend it - if that style of action platformer works for you.

Edit: Genkicolleen was a big fan of the games, IIRC.

I never played the originals of the C64 days, but I have completed the more recent Twisted Dreams and Rise of the Owlverlord games. It's definitely not a Mario clone anymore. It's a very good platformer that makes great use of its shifting gimmick so if it looks like something you'd enjoy then it probably is. With that said, Giana Sisters was definitely on the more difficult side. The difficulty increases rapidly after the first few levels and never relents. Rise of the Owlverlords picks up right where the original left off with brutal difficulty right from the beginning. I like my platformers challenging so I didn't mind, but other players might have more issue with that. A patch subsequently added an easy mode to the game, but I was already finished with the title by that point so I don't know much about it.

Now I don't feel so bad. ;) Thanks!

Giana Sisters my personal Mario, never liked the plumber but loved the spikey hair girl.

Played throu the game back in the days on the C64 loved the music, oh Chris Hülsbeck, and liked the monsters.
Friend of mine and me had to figure it out if we could land right next to the flame on the barrel, ah
so many wonderful moments of frustration and "haha now its my turn".
Once a year i fire up WinVice and play the game and it still holding up for me.

Now the new ones are good plattformers liked them, but i'm a little bit biased when it comes to
the franchise.

It's a great game. To appeal to authority, lowyhong loved it so much he had a Giana avatar at some point. No bugs (that I've encountered), great level design, clever puzzles, clever secrets. It doesn't have lives; it has checkpoints, and your rank in a level depends on collectibles, er, collected and how often you restart from a checkpoint. Keyboard controls are surprisingly ok.

Giana Sisters is casual game very fun with lots of re-gameplay. The music is great and the visuals of the game are fantastic. A sonic / mario hybrid with its own charm and keyboard controls are optimal.

Lame? LAME?? I broke three joysticks while playing Giana Sisters on C-64, one of my favourite games!

edit:
As for the Giana Sisters: Twisted Dreams I have it on Steam and PS4 and I think the game is quite good, if you like platformers.

I was talking about Giana Sisters: Twisted Dreams.

I played the C64 one - and loved it.
So, of course I played the new one, too.
It can get a little difficult - though that may just be me getting old. ;o)
Overall, I would absolutely recommend it to anyone into jump'n'runs.
Can't speak for the sequel (RotOl), since I haven't found the time (or desire) yet, to play it.
Can't say, why the second is cheaper than the first.

Trolled

I watched a gog twitch stream of it. I thought it looked very impressive. Definitely not a crappy Mario clone anymore (the c64 one was)

Wow, you can do that?
XD