Find your way to collect all seven stars. If you believe that there is no way to progress, try to think beneath the surface. The game has a end-screen. ;)
Tested in Firefox and Chromium!
Sounds are muted by default, but can be unmuted using the M key.
My time is 114.2, probably beatable.
Controls
Arrow keys - movement and portal usage
Space - jump
F - Fullscreen (if supported)
M - Unmute / mute sounds
Game don't show up? / Is slow?
If the game is laggy, try resizing your browser window. If the game don't run at all, please provide the exact version of the browser you're using, so I can fix it.