Yeah you have only one life but have 3 hit points in total and the blue line (Line of Recovery) heals you up to max health when you walk over it. Also the triangles can be used as a shield since they're bullet proof. One more tip is you can also jump outside the frame and stay there for 3 secs. There are many different strategies you can use to beat the game. Like shooting your Void ability outside the frame to pull them away. It takes a while to get the hang of all the mechanics and beat the game.