All of this sounds great so far, and I'll admit, Krater makes a strong first impression. The problems begin to crop up when it comes to actually playing the game. For starters, combat is generally very uninteresting. There is very little enemy variety, and their tactics are almost always identical - bum-rush your party, or stand still and shoot from afar. A few have access to special abilities like stuns and knockbacks, or can heal friendly units, but ultimately fighting just isn't that much fun. The same goes for your own party - mashing hotkeys on cooldown and choosing when to heal is basically all there is to it. Whereas titles like Diablo III offer up enemies that have different behaviors and require different abilities to deal with effectively, with Krater you've seen all the combat has to offer after about an hour, or even less. The same goes for level design - Krater has a handful of tilesets (caves, old factories/powerplants) and reuses them constantly with almost no distinctive features, landmarks, etc.
Then there's the character system, which sounds good on paper, but leaves a lot to be desired. The game has four attributes - Strength, Stamina, Intelligence and Focus - and these feed into the four classes, namely, Bruiser, Slayer, Regulator, and Medikus. Despite the names, these are basically tank, DPS, support and healer archetypes, the former two melee and the latter two ranged. The classes aren't anything special and, despite there being tons of randomly-generated mercs available for hire, they're all basically identical in everything but appearance.
This is largely because leveling in Krater is completely uninteresting, due to a lack of diversity or progression in skills - of any sort. While party members can be customized a little by installing attribute-boosting implants (you unlock more slots as the game goes on), the core abilities you have available will never, ever change over the course of the game. Some of the heroes available for hire do have different abilities (some healers have an area-of-effect heal, for instance, while others have a continuous heal beam), but these differences are cosmetic at best. Character progression is the bread and butter of any RPG, and yet leveling in Krater is unfulfilling in the extreme. While putting the emphasis on implants is in theory a good way to allow for respecs and more flexibility, it'd only really matter if the implants provided anything more than linear attribute boosts.
Then there's the issue of how experience is handled. Because all party members are basically interchangeable, and all bonuses come from implants, the actual leveling itself goes by very quickly. However, all party members are ranked from I to III, and are capped at levels 5, 10 and 15 respectively. This means you'll either have to pay for expensive training to upgrade a party member to the next tier, or hire a new one. This isn't a huge issue as I never got emotionally attached to any characters I made, but it further damages the feeling of progression. I can understand and appreciate the desire to have X-COM or Jagged Alliance-style disposable troops, but mercs aren't valuable enough for this system to actually work. Strategy and tactics games need to have a bigger picture that those smaller units tie into to make you care about them, and Krater doesn't have any such thing - someone dies for good? All it means is you'll be spending another hour or two grinding a new mercenary up to max level again.
Finally, there's loot. There's been a disturbing trend in action-RPGs lately, spearheaded by Diablo III in particular, of reducing all equipment to static DPS and armor values. I'm against this system largely because it destroys any of the distinctiveness between weapons - it doesn't matter if you use a sword, axe, or chainsaw, all of them are effectively identical because DPS takes priority over everything. Krater does avoid falling into the trap of DPS being the be-all, end-all decider (the discrepancy between item DPS isn't that big, making secondary modifiers more interesting), but as the only equipment available are weapons and secondary items (i.e. health kits, grenades, etc.) there's really no interesting choices to make at all in Krater when it comes to outfitting your party.
All of this adds up to an RPG that's, at its best, extremely shallow. Leveling mechanics are interesting not because players like to see shiny numbers go up (though that helps), but because leveling gives players new opportunities, skills, abilities and so on. Krater has the basics of a decent RPG system in place but the developers didn't seem to understand why all those stats, experience points and skills are interesting in the first place. In the end it feels a bit like a game made by someone who read what features an RPG is supposed to include in a book somewhere, but had never actually played one before.