Undulo

About the game

Undulo starts with a fox waking up alone inside an abandoned alien spaceship. The only thing it carries is a pulse gun, and that gun is the whole game: every shot pushes the fox in the opposite direction, so the way you move is the way you aim. Aim down to rise, aim sideways to cross a gap, and keep firing in mid-air to steer. Walking is the easy part; the ship is built for flying.

The ship is a set of connected areas with hazards, locked doors, gravity zones, checkpoints and enemies that patrol, fly or guard a spot. The same pulse that carries you also pushes the enemies, and the quickest way past many of them is to send them somewhere they cannot come back from. Hidden side rooms hold extra ammunition and other upgrades, and every area has glowing runes to collect if you want to reach 100%. Somewhere deep in the ship the reactor is about to explode, and that is where you are going.

It was made in one month by a team of five for the GitHub Game Off 2025, whose theme was "wave", and it shows in the details: the layered pixel-art backgrounds, the cave and pipe sections, and a soundtrack and sound design written for the game.

Playing it here

Click Play and wait while the game loads (about 29 MB, downloaded only when you press the button; a few seconds on a slow connection). Choose New Game, then follow the short messages in the first area, which teach the pulse. The game needs a mouse for the main pulse and a keyboard for walking and for the mid-air pulses. The pause menu (Esc) lets you restart from the last checkpoint or restart the area, and has its own options.

Controls

Tips

Aim away from where you want to go. The pulse pushes you the opposite way, so shooting at the floor lifts you and shooting at a wall to your left sends you right.

Watch your ammunition. The gun has a limited charge; land and recharge on the ground or at the ammunition pickups before you start a long flight.

Use the arrow keys for fine steering. The mouse gives you a big push toward the pointer, and the arrows give the small corrections in mid-air.

Look for side rooms. Upgrades and runes are often tucked in a small room off the main route, and a runes counter in the pause menu tells you how many are in the area.

FAQ

Do I need a mouse? Yes. The main pulse is aimed with the mouse pointer.

Is there a gamepad? The menus accept a gamepad, but the game is built around the mouse and keyboard.

Is it free to share? Yes. The code is free software under the MIT licence, the art, music and sounds are under CC BY 4.0, and the licences of the third-party material are listed below.

Credits and licence

Undulo was made by Foxy Trot Games: crisp_lad (team lead, lead programmer), koallary (level design, level art, music), ClownManGuy (animation, art), Screen (enemy AI) and foks (music and sound effects). The code is under the MIT licence and the assets under Creative Commons Attribution 4.0, as the page of the game on itch.io says. It runs on Godot Engine 4.5.1, also under the MIT licence.

• Godot Engine logo, Copyright 2017 Andrea Calabro, licensed under CC BY 4.0, shown in the credits screen.
• Git logo by Jason Long, licensed under CC BY 3.0, shown in the credits screen.
• Input prompts by Kenney, CC0.
• Godot Game Template by Marek Belski and Phantom Camera by Marcus Skov, both MIT.

One change was made for this site: the logo of the Godot Game Template is licensed CC BY-NC-ND, which does not allow commercial use or changes, so it was left out and the credits show the template by name only. Nothing else in the game was changed. The licence texts, including the notices of the libraries inside the Godot engine, and the source of this build are linked from this page.