I like the angry face enemy.

I enjoyed playing this one, the controls are responsive and the physics may simulate slippery ice , the mechanic is straightforward and shooting enemies will add to life , the gameplay is a good arcade style game,  this has good replay value, keep it up!

What the game offers works. So far so nice. I really like the grumpy smileys, they rule :D 

Now we could tweak some parameters a very little, to raise the duration of enjoyment drastically. If you allow me, I would like to make some little calls:

- Randomize the spawn positions. This can be "easily" done, by randomize the x value for the enemies spawning on horizontal axis and respectively randomizing y values for the vertical spawning enemies.

- Maybe avoid spawning enemies from the bottom OR raise the lower ground platform a bit to increase reaction time

- speed up the velocity of the enemies by taking into account the max score the player reached during a round (do not take the current score. That would decrease by getting damage, which would slow the enemies down again and take a round to infinite playtime ;)

I really liked this game and it is a great kickstart into the game dev journey. Glad, that you shared this experience with us :) 

Nice concept! If you decide to make any changes maybe add some more hazards to the level as time goes on to ramp up the difficulty.