Early access - NO multiplayer cooperative or competitive!
Having established this, though it is stated clearly, on to the review:
It is a hero-TD, meaning you have a hero (sic!), which kills (alot) of monsters, coming in a wave. Other meaning of killing monsters are, of course, towers (here called 'traps'). For each kill, you get money, which you spend on customizing and upgrading. It looks as Diablo (hero/skills/loot/leveling) is packed in TD-game (upgrading towers/research tree/customization). Graphics are excellent and so is the sound.
Both hero and traps have extensive upgrade possibilities, and you (probably, I'm playing early preview) can't have all of them maxed out - as you very well shouldn't. This means you can develop your own, unique playstyle. Thats TON of possibilities and potential replay value. Since it's not the only one, we shall call it TON-1.
MP coop *will* become available at some point (read the schedule). I expect that each additional player, with his own unique setup, will make gameplay different - I haven't seen this in work, but expect TON of variations, and we shall call it TON-2.
MP competitive will have players in two team pitted two against two (attackers who manage monster waves and defenders - or so I'm told). I don't have a clue what will be attackers options and how many different strategies and possibilities they will have, so lets say that, if done right, it *can* add a POSSIBLE TON of variations, call it possible TON-3
The Editor: yes, there is one. It's in the early stage. I don't know where its limits will lie, but if done right, player-made content can produce unique, high quality maps, introduce different elements and settings - this is PROBABLE TON of variation, TON-4.
Conclusion:
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Based on my many years of playing various TDs, and last five years spent as coodeveloper/developer/balancer for the one of best known and long-lived TDs around (no advertisement, though it is a mod and therefore, free) and having helped on several other well and not-so-well known TDs, here's my judgement:
This game has great potential. It is early preview, so all I saw was one hero in single player campaign and lots of stuff is still locked. I believe that full game will be a TD worthy of having, and certainly fun to play - whether you are an aRPG or TD fan, you'll find something intriguing to this genre mix-up.
But since I've detected TON-1 and TON-2 (totalling 2 tons) of certain variations, and, possibly, TON-3 and TON-4, I think think this will be game worth having and that players will return to it many times. Because of those tons of variations, of course...
Should I buy it?
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1) If you're interested in helping developers to find bugs, refine balance, propose new features (they're very open to this) and influence game development in general -
YES2) If you're interested in playing what is on the table, few maps, campaign, one hero -
YES - in just a couple of weeks/months there will be alot more.
3) If you're going to check MP availability, although it is *clearly* stated that there is not one at the moment, and then whine about it and even write negative reviews, then
NO, please don't bother
The game is in the playable state, there is no placeholders or missing graphics (in the part which I've seen, at least) - unlike many "Early previews" who are just a way to support further development.
Meaning, you can play it right away, with some options disabled. Which is what I am going to do, as soon as I finish this.