OK so I played through all the demo had to offer.
Movement seems fine now for the meteor part. When the blue aliens get thrown into the mix it becomes really hard again.
I think because they keep coming, so you can't fire and stabilize. Maybe freezing them or adding negative impact momentum to them might solve this?
Best way I found right now to deal with them is by staying at the edges since going over transports you to the other side, whilst the aliens don't tend to go over. So they float from the other side to you.
It is definitely doable (just finished the demo) but hard.
I also agree on the mini game. It is really unclear what to do. At first I thought you had to mash the button whilst in the green zone. This lead to accidental pushing when it flips the other way taking away from your progress.
Once I had the rules figured out (only once when in the field) it became hard but doable.
Hard but doable seems to be the theme for your game. Don't know if this is intentional
The art is lovely though, so keep up the good work