It seems the store wasn't working! The first level is by far the hardest to run, and you really can't progress if the store wasn't working :( Your reactions are meant to be pretty bunk until you get a few upgrades.
I was under the impression it was far more CPU limited, but I did most of my development on an i9-12900K with a 3090 so my perception is likely to be skewed.
Some notes:
'Energy' is purely a measure of 'score' and used as currency which you would spend in the store (if it worked!).
There is 'radiation' feature where the game randomly gives you the value of a single fission, I noticed you 'waiting for energy to reach 1000' and I had a chuckle LOL
Once again, thank you so much for playing and recording your gameplay, this is beyond helpful for me.