vested interest
Based in Gainesville, FL and Boston, MA

Release date:
26 February, 2013

Apple App Store
Humble Store


Regular Price:

App Store$0.99 US
Steam/Humble$1.99 US


simian.interface++ is the long awaited update to simian.interface, an abstract puzzle experience for simian participants of all ages and abilities. There are no explicit rules, no instructions, and very simple controls. Inspired by tabletop puzzles, modern art, and cognitive psychology experiments, simian.interface++ presents challenges that must be solved using pattern recognition, intuition, and experimentation. The update includes infinite_loop mode, which features endless combinations and variations of the level types in the core game and remixed music, level backgrounds, and story screens. Players who want to test their pattern recognition and reaction time can pursue a high score in timed_evaluation mode.


Originally designed as a mobile tie-in for a co-op game that was never released, simian.interface began as a Flash demo which required the player to move colored squares into a specific arrangement indicated by a picture-in-picture window before a timer ran out. Feedback from playtesting resulted in the removal of the timer and the preview window, making a more zen-like experience in which players had to use intuition to figure out what was expected of them. After a long process of iterating on a few simple game mechanics, the level order was solidified, and simian.interface was released on Flash portals. Not long afterwards, it was published for iOS by Chillingo with assistance from Bullseye-Studio. The reviews of the Flash and iOS versions of simian.interface were very positive, but there was a common thread to the negative comments: The game was too brief. Jon and Josh considered designing additional levels which could take months while adding less than an hour of new gameplay. After some open-ended experimentation inspired by Spelunky and Perfection., they developed an endless gameplay mode that remixed the mechanics and elements of the root game. To reintroduce a sense of challenge, a timed variation of infinite_loop was added, featuring a countdown timer and time-adding checkpoint system inspired by Crazy Taxi. After honing the gameplay randomization and adding a number of random elements to the art, story, and background music, infinite_loop mode was added to the iOS version of simian.interface (retitled simian.interface++). The PC/Mac version of simian.interface++ is now available on Steam and the Humble Store.


  • Mysterious yet intuitive puzzles for players of all ages.
  • An incredible soundtrack composed by chiptune artist Note!
  • The original simian.interface, now playable in full screen.
  • Infinite procedural level generation in infinite_loop mode.
  • Challenge your pattern recognition and coordination in timed_evaluation mode.


Original Trailer YouTube

infinite_loop update YouTube

Out Of Index Festival video with developer commentary YouTube


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Awards & Recognition

  • "Indiecade Finalist" Indiecade, Los Angeles, 2013
  • "Indie Prize Nominee" Casual Connect USA, San Francisco, 2014
  • "Official selection" Out Of Index Festival, Seoul, 2014

Selected Articles

  • "Smart, gorgeous and with a wonderful soundtrack..."
    - Tom Senior, PC Gamer
  • "There’s some very subtle, very effective game design going on here."
    - Jesse Singal, Boston Globe
  • "An intriguing trip into the unknown, simian.interface is a puzzler filled with delicious colors, sounds, and three dimensional shapes."
    - Greg Srisavasdi, Arcade Sushi
  • "I can’t quite explain how much I enjoyed it. I could describe it as therapeutic or meditative."
    - Ari Margo, Gamer Horizon
  • "It's a fun puzzler that'll fill your free moments with some unique challenges"
    - Kelly Hodgkins, Engadget

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About vested interest

vested interest is an indie game studio in Gainesville, Florida. The team is comprised of designer/artist/programmer Jonathan Yuhas and designer/writer Josh Leeper.

More information
More information on vested interest, our logo & relevant media are available here.

simian.interface++ Credits

Jon Yuhas
Design, programming, art

Josh Leeper
Design, art, sound fx


presskit() by Rami Ismail (Vlambeer) - also thanks to these fine folks