I got stuck at wave 5...

It says -2 aliens left.
Can I also just suggest that you give coins out for everyone so at least everyone gets 1 coin. Only 1st-3rd get coins at the moment. How often will the high score restart? Weekly?
I love how their games are kind of old school looking. It brings me back to childhood feels and makes me want to try. The screenshot above looks like Galacticus, if I remember it correctly. Do I need to buy PIXL in order for me to play?
Why didn't you just click the link and try the game? It is more like space invaders though.