I like that the strength of the beam does get affected the further away you are from the ground. The rockets turning red is also a great choice of conveying its lifetime to the player.

The UFO could be slightly smaller, it seems a bit too big relative to the screen. The rockets also shouldn’t spawn from the bottom like it’s coming out from under the ground past the sheep, it doesn’t make sense.

All in all, I had some fun playing it, and it’s a decent game. Keep it up!

Neat idea and very challenging. The randomness feels a bit off, I had runs where there first 10 spawns were no missile soldiers, and other times three to four were shooting at me.
Maybe start a little slower and increase missile velocity over time, it's over way too soon ;)

cool idea and it becomes challenging good job!