Now, i do like this than thw original, but increase the coin spawnrate from 5 to 10? You just made the game easier because coins are easy to get.

now while i do like the remix and will probably go this way and update the spawners so the enemies appear more frequently keeping it harder i can see that while making the game harder with more frequent eneimies you also made it easier by making coins fall every 5 seconds instead of 10. all the point of the coins taking this long to fall is so that you have to buy factories if you want to go far.

If the game is hard you are probably unlucky, zombies have a set chance of spawning every 5 seconds!