I installed Rogue Legacy yesterday and played a little bit. One thing I did not understand was up arrow showing up at someplace above my character. I naturally tried jumping but nothing happened. Did I miss something in the tutorial?

You should try Mutant Mudds.
I completely finished the game and found the difficulty to be very fair.

If only they updated it to have all the levels the Steam version has.

I'd like to cast another vote for Escape Goat.

I normally dislike platformers, but I really enjoyed that game. As Starmaker already stated above, it mostly requires planning/thinking, not fast reflexes. However there are some levels which do require reflexes and which took me forever to pass, but I eventually made it (I don't have a controller so I was only using a keyboard). Other than that, the game is fairly easy (excluded the bonus "All Intensive Purposes" levels). I would not recommend Escape Goat 2, which requires a lot more in the reflexes department. I tried it, but quit about half way through because I was simply not enjoying it as much as the first game because I was slogging through too many levels which require perfect timing.

The Steam version has additional levels? Ha, didn't know that.
Would you agree that the general difficulty of the game is not to high?

Don't know if it has been mentioned yet, but Abuse is certainly a platformer that deviates from the traditional genre. It really is an action platformer where you use the mouse to target and shoot, though it has been a while since I played it I don't remember the gameplay to be supertwitchy. It was freeware at some point but I think that it isn't anymore, it's still opensource though.

https://www.youtube.com/watch?v=i6_2ZGBZ0ZE

Yeah, pretty much.

Abuse is definitely freeware. You can get it from various abandonware sites, and from Desura without requiring an account. That said, it is a pretty intense action game and I'm not sure I'd recommend it to someone looking for a less reflex-intensive platformer. Abuse is like a side-scrolling version of Doom.

You mean the up arrow as shown in the attached picture?

When your character reach something he / she can interact with, there will be an up arrow showing and when you press up, he / she will interact. See if you have your key-binding correct

Thanks, I never thought to press up, just jump. Now I feel like my dad trying to use a new electronic device, someone kill me.

I can ssooo relate to this. I loved Limbo (Steam) for a little while...and then it suddenly got way too tough. Happens to me often in actiony-y platforming games.

As another reflex-challenged individual, I offer my thanks to all those willing to talk about how hard recent platformers are or aren't and why. Lemmings... I loved that game. I wish GoG could bring it here, especially the Christmas levels :D

My own favorite platformers are "Super Mario Sunshine" and the original Spyro 2 & Spyro 3:Year of the Dragon. "Super Mario Sunshine" (Gamecube, but it runs on the first gen Wii) is so much easier than other Mario games because of "fludd" which offers a hover function that I use very very often on all my replays. lol Have you ever tried the first Ratchet and Clank? Even with my slow reflexes, I can play quite a way into that one, and the storyline is very funny :D How about Portal 1?

As for new stuff - how about Casual Girl's suggestions?

How about,snap.