REFERENCES
https://www.freesound.org/people/fins/sounds/172207/ - portal.wav
https://www.freesound.org/people/fins/sounds/171520/ - button.wav
https://www.freesound.org/people/fins/sounds/146726/ - jumping.wav
https://www.freesound.org/people/Rocotilos/sounds/338961/ - letter.wav
https://www.freesound.org/people/MultiMax2121/sounds/156859/ - error.wav
https://www.freesound.org/people/edtijo/sounds/240376/ - tune1.wav
http://www.fontspace.com/codeman38/press-start - PressStartK (codeman38)
CONTROLS
A key - move left | D key - move right | Space - jump | R key - reset level
F key - toggle FPS
OTHER
Firefox issues: music might not work, must move mouse to re-click icons
Chrome issues: sometimes suffers from lag
(Chrome recommended)