Some internal stuff going on mainly... added stats to monsters and towers, which paved the way for upgrading towers, which you sorta see here! That's the upgrade 'menu' - the two smiley face buttons will one day instead display the two advanced tower types that Rock Towers can become.
There's also a big circle showing the range of the tower. These towers just toss rocks horizontally, so they don't really have a big circular range (they can't shoot through walls either). Originally I implemented a thing that actually scanned out for obstacles, showing you a true range (it didn't actually account for the fact that they throw sideways though, just got stopped by walls). But there were several problems with it, to the extent that just scaling a picture of a circle seemed like a much better idea! It's a lot prettier too. It's up to the player to actually look at the terrain and figure out where the rocks can really go.
Currently, upgrading the tower just puts those yellow dots above it, seen on the upper tower. I'd like to have the tower actually get fancier looking, but I suspect I won't be doing that in this game. There are a lot of tower types.