Not exactly a new game, but
Transformice is heading to
Steam on the 30th and will still be F2P ("ethical" aka cosmetic F2P). As Newgrounds was how I got into indie games, it's pretty cool for me to see some great Flash games hit Steam. Haven't played it in years but I'll check out the Steam version soon.
Very confused about what does/doesn't hit Steam lately. Transformice is huge but honestly wouldn't have expected them to hit Steam, maybe it's a new market for them. Some games I've never heard of seem to end up on Steam with insanely low SteamDB player counts (are those accurate?), other stuff seems to sit around in Greenlight for ages like
Social Justice Warriors. Transformice I can understand being big enough to skip Greenlight, other stuff seems really random.