It is fun and simple to play.

Great game, makes me thing of old Newgrounds games.

Only criticism I can think of would be adding some kind of sound to the game be it sound effects or background music.

Very interesting game that reminds me of Flappy Bird.

I quite liked the randomly generated terrain (I assume it's randomly generated) and the difficulty is just right for a game of this style.

I also liked how the high score counter at the end of the game climbed up towards the highest score and then began to slow down as it approached its destination value.

Great job!

This is quite a fun and challenging game however I didn't like the lack of audio and felt that it would have made the game much more fun.

This is a very nice recreation of this game, i used to play this game over and over in browser at school.

The change you have made to the helicopter from the original seems strange though. The original has a green helicopter which sort of keeps with the background, i feel like maybe yours is a little out of place.

Some background music or helicopter sounds would also be really cool to add some depth to this.

Overall a fun game, i still have sat here playing it way longer than i should.

Really enjoyed playing this once I got the hang of it.
Simple concepts are often the best and this is a great example. 

Things for your consideration:
-The static helicopter image might have been better with an animation but I did get laugh out of it being the way it is. 
-The monotone nature of the cave colour gets a bit repetitive and could do with some variation to keep the player engaged.
-Faster restarts
-Music and/or sound effects

Good concept, responsive gameplay. I would work on adding an animation to the helicopter, and maybe having it angled up/down when moving.

Nice game concept and smooth mechanics. Reminds me of the arrow stage from Geometry dash. It's  nice level of difficulty, setting a challenge but not being impossible

The only things I'd change would be to add an animation to the helicopter and also make the restart time a lot quicker, as you have to wait a while before you can play again. Other than that its a nice game.