The Windows prototype of Perennial is a decent chunk of a minimalist metroidvania with great music and noisy sound effects. "The intention is to have smooth technical operation combined with a pure aesthetic that isn't gummed up by standard video game tropes like words," developer Badspot says on the Steam Greenlight page.

Two buttons and directional arrows allow the player to jump, dash, dig dirt, punch walls, and head-bash blocks below or above. Though common in a metroidvania, I didn't find any totally invisible walls in my playthrough. However, I did crawl through some conspicuously jagged walls that really opened up the game world.

Be sure to turn off Sticky Keys, as SHIFT is the jump key, or use a joystick/joypad, which is supported by hot plugging (or hot swapping, if you will). Finally, be sure to enjoy the ending. The real one.

The prototype download link is available on Perennial's Greenlight page.