Thanks for the feedback! Matching 4 or more only provides a bit more resources (linearly), I had a nice-to-have todo to make 4+ matches spawn a 'super tile' that would provide bonus resources if matched, but it never bubbled up in the queue before the deadline.
Both enemy balancing and upgrade cost balancing were pretty rough to get just right in the short time of play testing the final values towards the end, there were a few last minutes tweaks to try to ease the difficulty a bit, but I also wanted to avoid making it too easy breezy.