Platformers are one of my favorite genres and Rayman Origins is one of my all time favorite games. I would recommend starting with the following. I'm mostly trying to name historically important games and hidden gems/less popular games that were really well designed. There are a lot of games that Im not sure about whether to include them or not. Games that were great¬able but too generic to be worth mentioned/too similiar to other games I listed (all the excellent lisenced games for 16 bit systems, Mega Man 3, Mega Man 7, Commander Keen games etc) or games that were innovative and influental but outdated (like Prince of Persia and Another World)
8 bitMega Man 2
Super Mario Bros 3
Ninja Gaiden
Castlevania
Metroid
Turrican 2
Fantastic Dizzy
Bucky O Hare
Mr Gimmick
Ducktales
16 bitMega Man X
Super Castlevania IV
Rocket Knight Adventures
Donkey Kong County 1&2
All the sonic games (Sonic 1, 2, 3, Sonic&Knuckles, Sonic CD)
Castlevania: Rondo of Blood
32 bit/64 bitJazz Jackrabbit 2
The oddworld games (Abes Oddysee and Abes Exoddus)
Crash Bandicoot 1. Ok, this game is a 3D platformer, but it includes some damn fine 2D platforming segments. The same goes for all early Crash Bandicoots.
Mischief makers
Castlevania Symphony of the Night
Since you love Rayman Origins, its worth giving the original Rayman a try. Its not a groundbreaking game by any means, but beautiful and challenging.
Tomba, Pandemonium and Klonoa are notable and very good 2.5D platformers from that era.
PS2/modern eraDonkey Kong Country Returns
Mega Man 9
Sonic Generations
pierrot wrote:I'd also recommend a couple other oddity platformers on the Mega Drive by Game Freaks (of Pokemon fame): Pulseman and Magical Taruru-to kun. Pulseman is probably the better of the two, and I know for sure that it's on VC. Taruru-to kun is much more niche.
Mcdonald's Treasure Land Adventure is an often forgotten Treasure platformer on the Genesis. It's relatively short and easy, but I think it's still worth a look. Tempo on the 32X is not exceptionally polished, but still pretty fun.
As good as those games are, I dont see any reason to recommend stuff like Tempo and Mcdonalds tresure land, not to mention Japanese imports, if he is a total newbie to the genre.