The energy loss is actually exactly steady. It drops at a set rate per minute, it's just that during the day I've sped up time so you don't have to sit there for twenty minutes waiting for it to be night again. And you found the exact strategy I had in mind lol It could maybe use a little more balancing, but I aimed to have it that if you got about eight hours of sleep, you'd start the next night with close to the energy you started with the previous night.
And yes, clearing the board gives you extra progress. The particles came about precisely because I was trying to draw attention to, and encourage, it. Doesn't seem to have been as obvious as I'd hoped though. lol
Thanks for playing!