Very fun! There is a fair bit of downtime after sending the first couple of rockets as you wait to get enough money to send the next, but once you get a high enough population, it's a rush to send as many as possible. If anything were to be changed, I think I would suggest adding a button where the player could generate a small amount of money on each click, just so they have something to do instead of waiting to get the money for rockets early on. But this is absolutely great for 3 hours! I played it a couple times to try and get a higher score, and I managed to get a population of 61 billion the second time around. :)