I play II, it's a decent little game but I believe it suffers from some of the same problems as the first and some new problems as well.
DD1 was one of my favorite games though, my hours played in that is embarrassing MMO level high
If the second one stays priced at 15-20$ it will still be worth it, but this company has just gone in circles
I think they had an amazing idea with DD1 and then with 2 first it was a shitty MOBA, now they are trying to reinvent things with DD2. All they really needed to do was make new characters, new towers, better/new maps, fix the "end game", etc. I mean it will never be LOL or whatever but they could have had another huge success.
Anyway I have not played since the last patch so some of this may be off but general opinions:
-Maps are way way better. Not only do they make more sense and for the most part seem to have better pathing aside from some odd bu(pre-alpha) they are just so much more interactive and fun. There are levels you call pull/shoot to release waves of water/gas/fire that takes out entire waves of enemies. The gates have little pink lines showing the path monsters will take to the "crystal". There are "mini crystals", which you do not have to defend but if you don't you make things harder. Like a drawbridge lever for instance that if you let fall now makes mobs spawn through the bridge where they didn't before.
-Generally speaking towers and heroes are the same, with some minor changes that won't be too foreign. They did seem to get rid of tower range as a stat which create some problems. These new spear guys can pretty much outrange any level 1 tower causing some annoying problems early on. Upgraded towers get buffed just like before, increasing their range so it's less of a problem, but can still pose a threat if the little guys form a wall protecting them(think orcs in front of archers allowing archers to shoot).
-Towers now have some combo crap. So if you freeze a mob with cold tower, then launch it up with earth tower, it breaks on land like Terminator 2 and liquid nitrogen. There are other combo's as well. Makes using different heroes and working as a team a bit better
-You seem to have a huge excess of defensive units now. Not sure if this is an "alpha" thing that will change or what. But the current focus seems to be on tower upgrades over tower numbers and good build locations.
-They changed stats recently, but I have not had a chance to really dig in at it. Basically every item has a primary stat and two secondary stats, blah blah. I'm sure they will change it again before launch but it seems like they are trying to move away from the everyone gets its all crap, not sure I agree but this is one of those "how much power should I have at high level" conversations that mucks up MMO threads too
-The new item upgrade system sucks. I hope they change it. Instead of just mana you need gold, which you get by selling items(just like you used to get from mana) BUT you also need....items. So now you have to jump through hoops and do all sorts of strange shit to upgrade instead of just selling items and using mana. All they did was add a level of obfuscation without making the system interesting, different, or more challenging.
-New enemies, good variation and seems fun so far. No complaints
So yea, they need to improve a few things but overall it's fun...it's DD!