Well that was quick. Ikaruga only shot its way onto Steam Greenlight the other day, and it's already emerged from the other end of the Valve's giant approvals machine, covered in a viscous, sticky substance it's probably best not to investigate too strenuously. It's joined by 36 other assorted things (most of them games), including sci-fi roguelike Steam Marines, platforming roguelike TowerClimb (not to be confused with Towerfall), and lots of other things that aren't roguelikes - if you can imagine such a thing.
The full list is below. There's some great stuff in here, including action-horror Source mod Underhell, retro platformer Tiny Barbarian DX, the beautifully illustrated adventure horror Neverending Nightmares (pictured above), and a hell of a lot more.
Aartform Curvy 3D 3.0
Alien Swarm FP
Axis Game Factory – AGF PRO v01.0
Blood of the Werewolf
CastleMiner Z
Elder Sign: Omens
The Fall
Fester Mudd: Curse of the Gold
The Fifth Day
FOTONICA
Fortress Forever
Fran Bow
Half-Life 2: Capture the Flag
Hot Tin Roof
Ikaruga
Infinity Wars
InkFish
J.U.L.I.A. Enhanced Edition
Metal War Online
Montague’s Mount
Neighbours from Hell Compilation
Neverending Nightmares
Nightmares from the Deep: The Cursed Heart
Portal Remake Mod
Ravensword: Shadowlands
Real World Racing
RimWorld
Starship Corporation
Steam Marines
Tiny Barbarian DX
TowerClimb
The Sparkle 2: EVO
(un)Lucky7
Underhell
Universum: War Front
Violett
Wrack