These are some of my thoughts on the matter:
-Races/classes:
I love the balance and flavor of the races and classes. One of the best features of the game. In a game like Dungeon Crawl: Stone Soup, for example, a lot of the combos are just plain weak. In Incursion there are a whole lot of viable options; some more powerful than others, but overall balanced really well. I especially love all the different schools Mages can specialize in. With so many features to play around with, no two runs are the same! I also adore multi-classing and prestige classes.
-Feats:
Also balanced very nicely, for the most part. Another fine aspect of the game, further adding to the character type. A charismatic Warrior plays quite differently than a Cleave-based one, for instance.
-Skills:
This is where things get tricky. For the most part, the system encourages decision-making and good strategic thinking, but my main gripe is that almost every skill is nearly essential to survival, so I often end up spread too thin on certain classes. Makes the game feel heavily biased to characters where you pump up INT, as well as playing as a human to get more access to certain skills. You almost NEED certain skills, such as healing, spot, listen, searching, escape artist, etc.
-Poison/disease: They add a layer of strategy to the game, but I think they're kinda over-tuned. Not taking the healing skill is just asking for a slow death. Even then, when you're just starting out with the healing skill it is quite difficult to undo the diseases and poisons of the dungeon. Resting a lot to try to remedy the situation just makes more enemies and hunger problems arise. I wouldn't get rid of diseases and poisons entirely; maybe just nerf them a little bit?
-Traps:
Seems to me that half of the trap varieties are not too bad, but the other half...whoo-boy! Poison, as mentioned, could be deadly, but perhaps even worse are the traps that outright destroy some of your items, including your main weapon! At least Warriors can use their oils of transformation to make a new weapon, but it feels particularly devastating to melee-oriented Priests and Barbarians. My idea is to make the traps damage items but not destroy them in one fell swoop.
After all, all that setting off a trap does is teach you "don't step on traps," which is kinda strategically hollow; you can't avoid exploring the dungeon, so all you can do is spend your precious skill points/feats to try to avoid them in the future, leaving you with less skill points/feats to spend on other nifty stuff.
-"From the shadows..."
I have been killed in one hit a few times so far. No warning, just brought to 0 health from full in a single turn with no recourse. Again, you can spend resources to make it less likely to happen again, but it's just plain cheap. What especially pisses me off is that it happened while I was playing an orc Warrior focusing on shields; they're supposed to be tanky!
-Exploration/UI:
A bit clunky, but otherwise good. In a perfect world Incursion would borrow some features from Dungeon Crawl: auto-explore and ctrl+f to search for items/features, and more. (I realize the odds of this happening are slim-to-none, but I might as well mention it anyway because why not?) I also don't like how you auto-loot certain items that your character has no real use for, like some types of shields.
-Enemies:
I mostly love the monsters of Incursion. The only thing that really annoys me is enemies who are practically invincible, not taking melee or spell damage. Some are especially picky in what can and cannot harm them. Other than that, I wouldn't mind if some easier enemies got buffed to be slightly more dangerous.
-Resting:
I like the system and the "risk and reward" element it brings, but it's yet another aspect of the game where you almost have to spend feats and/or skill points to avoid a cheap death. (I have a sneaking suspicion that I rest more often than most people who play this game do.)
-Alignments/Religion
I can't comment much on this; I usually play neutral evil atheists to avoid having to deal with conducts and kill whatever I please, and I'm glad that it is a viable option. Maybe someday I'll try a Paladin or something.
-Bugs/Glitches:
I'm pretty sure that the bugs I've run into are well-known. Some of them are run-enders and/or really annoying.
-Overall:
Incursion is one of the most complicated games I've ever played, and I love it! It's one of my favorite games of the genre. I absolutely suck at roguelikes but I'll keep playing them anyway! Feel free to discuss the balance of the game.