SickBrick is an action-oriented Sci-Fi FPS with modern graphics and oldschool gameplay inspired by Portal and Serious Sam. Out now for Windows, Linux and Mac! (linux version uses a wine wrapper)
It's a straightforward FPS with some stuff added like two levels where you drive a tank and little platforming parts to break up all the robot-killing :D The game consists of 15 levels mixing indoor and outdoor areas. You're forced to do tests for an unknown robotic mastermind. As you go through the tests, you slowly unravel the story through log files of previous test subjects.