Glad you liked it.
You can get hints by reading about lucid dreams and what does work and what doesn't work in a lucid dream.
*SPOILERS BELOW*
Player "health" is the Z's in the top-left. You lose health when interacting with "real" objects aka clocks running clockwise and normal mirrors.
Top-middle there are your "points" which you get by interaction "unreal / odd" objects. After 10 points you win the game and get access to infinite-gamemode, there you can gather power-ups as much as you like and get your highscore.
Did you notice you can play in the main menu also?