The game is fun, I love tower defense games and this was no different. But I do think that the enemies could use more health, defense or speed since I was able to clear the levels with only one tower. I also think there should be an ability or upgrade for the character to carry more stardust and maybe do a dash since the map felt a bit too big to get from one side to the other. You can also add a invisible wall for the stardust since I often kept throwing them off the map by accident and other times they fell off by themselves when multiple enemies died on the same platform.
A tower you could make is Pluto, small but deadly, I think it could slow or freeze enemies and maybe if you want make, the ground around it become ice to boost your movement speed.
I think a volcanic area could be nice, would block the player from walking on lava and placing towers on it making them think on how to better use the terrain.
The game was smooth for me, but I do think there should be a bit more sense of urgency between waves maybe by adding a timer for the next wave
The UI is understandable, although I do think it should tell the player what buttons they can use and what the towers mean
Maybe enemies could affect the player in various ways like an enemy that leaves a trail of slime that slows the player if they cross it or maybe they cause a small explosion that if the player is nearby they get briefly stunned for a few seconds unable to move or interact with things, it makes them more dangerous than other enemies making the player focus on it in different ways depending on how they affect them
I think enemies should be more difficult, I only needed one tower to put on an intersection and I didn't have to worry about the enemies again. I think a way to fix this could be by making multiple paths an enemy can go, that way the player is obligated to add more towers and upgrade them.
Edit: I enjoyed the new towers and enemies I think it made the game much better and more fluid especially the upgrades and elements
I do think more different environments would be better with obstacles that the player must overcome such as lava and more explanation on mechanics like elements and effects from towers.
Great improvements so far can't wait to see how it comes out in the final game.