Good to see such an amazing update. Here are my thoughts on what could be improved and what stands out for me.
First of all, custom music is a must here, especially different tracks for a different type of areas, two to three minutes tracks doesn't eat too much of space, but I am sure you are planning to add it as this is not final.
What is more, you could really use more of custom icons, specifically custom icons would be best there where you see them a lot, for example, hero icons. If you can't find any good icon, you can simply print screen model's face and using Button Manager tool found on Hive make a decent looking icon.
Terrain is very well developed, but at some areas is looks very empty, for exmaple, those rocky paths, it is like one tile and no doodad, well it looks like it. Some small rubble on ground in such areas would do magic.
Custom UI would be really cool as well, but that's for the future I suppose. Not sure if such thing should be asked, but voice acting would improve the game a lot. It might be hard to achieve due to lots of text though. What concerns sounds, you could use some lines from standard units and run it when talk begins. Even though it would not say what is written, game wouldn't look so mute. Same goes with bossas, especially bosses. You can make a periodic trigger or trigger with conditions depending on boss fight phase what lines to run and these lines could be taken from ordinary heroes, for example, Lich voice. This would truly add more experience to the battle scenes.
On the good note, I really enjoyed environment art in the cave of spiders, it looks gorgeous. Spider eggs idea and overall look as well as spiders going down on webs is just fantastic. Edward boss looks badass. Also I really liked boss running to get some armor, looks very realistic. Treaure part looks very shiny and treasure-like, it would surely make me feel good about finding some of that shiny and precious stuff. Good job, this will be big.
