I enjoyed the game but after 50% or so  it felt too slow with the stat caps since it was unclear how I could raise them

The gameplay itself feels a bit light, but the visuals and systems are nice and polished. 

I would like to see more upgrades, I was at a point where I'd bought all the upgrades and there was nothing to do but wait 10 seconds for each self and/or wait 1-2 minutes to manually purchase one (because they each costed 50k+). At that point the only gameplay left was to sit watching the 'Unreviewed' screen, click the stats button, and accept whichever number was green. And this process felt a little slow since there was no way to upgrade my auto collector, etc. 

I also think that if the player could purposefully create a 'build' by choosing an imbalance then it would be cool. Like instead of everything being raised equally over time just to reach 100% in each, if you could intentionally pursue a disproportionately high 'Social' facet which would then have some affect like gaining more energy from each self, etc.

This is a good framework for a game, and the first few minutes I was really enjoying diving in - it just got old a bit due to the actual gameplay loop itself kinda running out of steam once you buy all the upgrades, I feel. (although I left mine running afk for a few minutes by accident so maybe that messed up the balance a lot somehow)

This game is quite addictive. Nice pacing. Most of the gameplay was easy to understand. Probably one of the few I'm coming back later to finish it up. Good approach with the theme. I have a hate/love relationship with games that looks like a spreadsheet 💜

The one thing that I'm still not sure about, is that why I would want to merge selves when they produce energy? do they continue to produce energy?

It's not bad, but it's not great. Watching the Selfs bounce around is quite fun and some of the upgrades were pretty useful, however:

1. I wanted a reason to increase facets beyond just "it's how you win the game". Why not give me certain bonuses depending on how high they are? Or something special for maxing them all out (at the current cap)?

2. The cap has no indication when or why it increases. I can only assume it's based off the total number spawned, but I wouldn't be able to even guess how many corresponds to the next 10% increase. I almost quit at 50%, saw what got unlocked then (nothing too interesting), and dropped after getting 60% in everything. I would've at least tied progression to the user maxing all the facets in some way.

3. A lot of the automation doesn't scale well with the increasing Self cost. I would've loved to upgrade that 2 energy for 0.1 selfs/s to like 20 for 1/s. 63 energy/second means it's still a long wait to the next Self at over 8k.

I can see what you're going for, and it's a good base, but I think it needs more upgrades and better reasoning behind the facet cap. With further development, this could be great!