Comment on: Play games and learn
Bunch of languages
CodinGame -- a bunch of games where you need to write behavior for some agent.
Hacker Rank -- problems grouped by domains.
Codeforces -- competitive programming, somewhat contest-oriented. It's still possible to solve problems without participating in these contests.
UPD: Code Combat -- feels closer to game, mostly JS and Python focused (also has CS, Clojure, Lua and Io as of now).
Comment on: Algorithms visualization
"Visualizing Algorithms" by Mike Bostock
http://bost.ocks.org/mike/algorithms/
A bit of everything in there (sampling, shuffling, sorting, maze generation)
Well, yes, maybe it's not really a game (as well as Hacker Rank, tbh).
Still, I feel like the only major difference between those and, say, CodingGame is that they don't have visualizations. Maybe some people are fine with this.