Platform Pixels is a mobile-first 2D platformer meant to be simple, easy to learn, yet extremely difficult. If this is your first time hearing about it, check out the Intro Post that I wrote on my blog.
The game is currently under active development so feel free to follow @PlatformPixels on Twitter to stay up to date.
There are currently betas available for Android and iPhone. Pick your poison.
To join the Android beta, join the Google+ Beta Community. After that, click the link in the instructions to opt in and install the app. NOTE: You should go through this process on your phone as some users have reported that trying it on desktop gives a "server error".