Fun incremental style game, especially with a good payoff for progression using the letters! I enjoyed the color scheme used and how cozy everything felt, alongside the relaxing music. I have two pieces of feedback:
1) The upgrade menu could be more responsive. Maybe have visual indicators for upgrades that have already been bought, and have the text underneath change on hover (rather than the current system where it is stuck to the message it was at the last click)
2) A bit more animation work on the background (like the clouds moving) would add a lot of juice and gamefeel for me personally
Beyond that, I had a great time with this project. Good job!!