It's alright, but I've seen this template used here before and the problems are similar.
Mainly, in endless games, you want to add something to keep players engaged, even though the gameplay is repetitive. That usually means introducing new elements and altering the gameplay whenever you reach a certain (score) threshold.
This game so far has only a single gameplay mechanic which can be fun for two, three minutes… but personally, it doesn't matter to me that much whether my score is 20 or 200 – there's nothing new to see behind the next corner, no NG medals to be won, no scoreboard to compete with other players etc. The speed increases, so eventually, the game ends.
The best improvement would be adding new gameplay elements, i.e. obstacles to jump over, going up/down (not just left/right), gaps, different kinds of surfaces etc.
Restarting the game is broken, though. The high score doesn't carry over and the block random generator doesn't start, so when you fall off, you have to reload the page to be able to try again.
Also, the character starts floating when you're close to the edge.