A downloadable game for Windows

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Welcome Petra, to planet Gaia. This is a dangerous planet home to valuable rock creatures who thirst for blood. They drop precious ore, and the rock creatures breed at an alarming rate. Your mission is to cull the herd as much as possible while also harvesting their valuable ore.

PETRA is an bullet hell survival game centered around farming for upgrades for your character. It is an endless game full of randomized variables, such as the appearance of the map, locations of upgrades, and the enemies themselves. Additionally, because Petra is only human, she constantly needs oxygen to breathe while on Gaia. Between fighting rocks and hunting for oxygen, it's no surprise that Petra's situation can quickly become hectic and out of control, but for her expertise it's no problem.


  • WASD to move.
  • Left Mouse Button to shoot.
  • Space to upgrade a stat (when next to the appropriate merchant).

Just in case you were curious...

Enemy Mechanics:

  • Enemy difficulty is based on the amount of upgrades the player has bought.
    • Each enemy has "potential" points that it spends to upgrade either its speed or damage.
    • The potential points and HP scale with the number of upgrades.
  • Enemy population/spawn rate is based on how much time has passed.
  • Rocks don't have fantastic eyesight so they only rush you when you get close.

Known Issues/Bugs

  • Difficulty not balanced well so after like 5 minutes of playing you get swarmed.
  • Merchants might randomly talk even when you're not close.
  • Sometimes pushing space doesn't actually buy the upgrade.

This game was developed across 3 days  for the "Potluck Game Jam" (https://itch.io/jam/potluck-game-jam) where 3 random themes were chosen: lasers, breath, and random.


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Click download now to get access to the following files:

PETRA.zip 17 MB

Development log


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Fun game. Very nice pixel art.  The rocks and upgrades from wandering merchants was a good idea. It made it quite addictive!