The AI definitely needs some tweaks. It has changed a bit since this build. Upgrade costs have increased while also becoming more powerful to make for more meaningful decisions. The AI won't just be buying all 4 upgrades anymore. I still have more adjustments to make though to the AI's decision making.
The shop currently has a slight golden flare around it after a refresh and the player hasn't looked at it. I agree that it isn't visible enough, so I just changed it to make it more noticeable. Also I have been adding all the audio the past few days and there is now an audio cue to signal that the shop refreshed.
I plan to participate in Steam Next Fest next month with a demo. Still a lot of work and testing to get done. Thank you for playing and giving me feedback. I'm glad you enjoyed it!