This is a solid entry and impressive, given that you didn’t use an engine but programmed it all.
I enjoyed the Star-Wars-trash-compactor vibe that I got from the blocks racing in from both sides, and the random generation worked very well except in the cases you mentioned where they spawn too near the player at the start of the game.
I got a disproportionate amount of pleasure from the fact that I could switch the Jacko lantern’s light on and off by clicking on it. That brings me to the point of the artwork: simple but very clean and appealing. I really liked the music loop for the opening and credits, and it contrasted nicely with the motivating action music of the main screen.
I would add a brief instruction to the game to save people time figuring out the drag and drop mechanics. Ultimately, it would benefit from a more challenging controller, but I’m sure that presents different programming or design challenges.
I enjoyed playing and hope to see more of your work!