Nice work! I really enjoyed this take on the theme. I never played the old Quake/Source games, but I had fun rocket jumping around and trying to skip parts of the levels. Played through all the levels twice.
My only complaint is that the controls felt very slippery. It made it very easy to slide off a platform into lava, leading to a full level restart.
Were the cubes meant to heal you when you shot them or just when you touched them? Regardless, shooting them does heal you, and it feels a bit cheesy!
Overall, fun game. I enjoyed it!