Love the art in this game! It’s very pretty, and a decent amount of fun. I enjoyed the progress bars everywhere, for upgrade affordability.
Balancing wise, I’m unsure why the future is so much stronger than the past. Especially since they give out their rewards more frequently - I’d expect the slower one to give enough that its spare time/second would be higher, to make up for its low frequency.
The game gets a bit stale about half way through. Spare time is a bit of a closed loop, game design wise. The only thing it’s used for, apart from increasing its own gain, is buying the upgrade to increase energy capacity. But ultimately those unlocks aren’t very expensive and you’ll have enough to afford every age around midgame.
I’d have loved to see some way to increase energy gain through any way besides dying. A lot of the end game was just spent waiting for energy to increase so I could go to every single age, which was the only thing I could see that could potentially progress the game, if there was any more to see. I was a bit disappointed when nothing happened after unlocking the last one - a simple “You win / the game is over” screen would’ve been nice.