Thanks ollie_d, I have actually continued working on this as it was quite a fun idea. I have balanced the spawning of the enemies, health, gold income, scoring and I also limited the player so that they can only have 8 platforms up at a time. Instantly made it more like a game where you have to puzzle around at the beginning so you can get the most of your setup.
I also made it possible to sell entire platforms for half the price. And I added a big laser turret.