Free to playScreenshots
From the Steam store
Cloudwalkers is a free, short, fast paced shooter platformer set high in the clouds! With 6 exciting levels the game is only about 15 minutes. You can choose if you want to speed run it as fast as possible or take your time shooting all the aliens to score the most points. The game itself may be small but the fun is unlimited! Gather your friends and see who can score the most or get the highest time! Be careful when shooting though, as you gun overheats and can kill you if you're reckless! The entire game is completely open-source on GitHub too! You can check out the code, mod it or even use it as a framework for your own project.
