What I see here seems fairly promising so far. I look forward to seeing development progress.
But I gotta be honest. All the Half-Life/Source Engine sounds are really distracting and take away from the atmosphere this game could otherwise have. I really hope you reconsider this aspect of the game.
The Portal-themed tutorial feels disjointed when compared to the rest of the game as well. It would feel better in a wilderness/research lab setting like the rest of the game, rather than Aperture Science. Consider replacing the text-to-speech voice with text tooltips or environmental cues instead.