I've had a great time so far, amazing work Larian, and I want to help improve the game, so here's my thoughts so far.
It seems like damage is calculated incorectly sometimes, the ability modifier is not added to the damage acording to my log. Crits seem to do to little damage as well, im not sure exactly how crits work (is it like in 5e?) but i crited for 2 damage i think wich was odd. (Also, the crit animation could use improvement, the "20" die just makes it hard to see what is happening.) I've had hits with a quasit familiar that is supposed to do 2d4 damage yet dealt 1 damage to an ogre. This might not be a bug, since damage reduction is a thing, but if it is, now you know
Quasit familiar can be exploited by summoning a new one after the first use their fear ability that resets on a short rest. There is no cost to just summoning a new one and have that ability ready again.
Ogres that throw rocks make the rock land in the air and the target is placed above it floating in the air. I had a fight where this happened 2 times, so there were 2 flying rocks at the end of the fight above eachother and my character floated above the upper one in the roof of the building.
My theif rouge was able to use 2 bonus actions after I leveled him up, but after having a long rest that ability is no longer working.
Rogue sneak attack does not seem to work correctly (I know you have to chose the sneak attack - attack, but sneak attack damage is not applied when it should be it seems somethimes.) And my sneak attack don't seem to deal 2d6 damage at level 3.
Personal opinions about the game:
Its very good generaly and playing a video game based on 5e finally, is amazing. However, there are a number of features that have been removed or changed (or might be upcoming features hopefully.) that I think would be better if they were more faithful to 5e, I do however understand the need to change some of them. How reactions work is for example very understandeble. The change to some class abilities is also understandeble, like the thief get an additional bonus action. That is a cool change, I imagine it was made becaue the thiefs normal abilities in 5e doesn't work well in a video game setting.
I don't like the jumping mechanic both for combat and exploration. In exploration it is very slow and awkward to make each party member individually jump, very tedious. This can be solved with characters atomaticly jumping with you if they are chained to you. (Yes, everyone can not jump as far as eachother, but just make a "party jump" button or something that has the shortest jump distance range in the party, and everyone can use that.) As for combat I just don't like the jump, it makes movement across the battlefield way to easy, in 5e it is a cunning action thing wich works much better and I think giving it to every class along with hide is a mistake and takes away from the rogue a lot (and the rogue is not compensated in any way it seems). I'm genaraly not a fan of the new bonus action uses, it just feals weird and takes away from other classes that have similar abilities, like the monk/fighter that can push people away with their attacks and so on.
Turns in combat is confusing and I'm not sure if it is a bug or not, but sometimes some of my characters don't get to act in combat, mostly on turn 1 when it's their turn. Is it because of surprise or something? It happens in fights where surprise should not be a thing however, and it's unclear what the cause might be. I know you can make your characters do turns in different orders while on the same initiative, so that is not the problem here.
The range of opportinity attacks, it would be nice to be able to see indications of how far they reach. (They also seem to have quite a bit of range.)
Reciving such a boost to hit chance simply from being on the high ground seems like a bit much, and the amout if higher up you need to be is not much at all. I think a better way to give advantages to high ground would be to have high ground provide strong cover instead to the one who have the high ground, instead of making them hit easier.
Better tooltips would be nice, Shatter for example does not say that it is an AoE at all in the description, wich is a big selling point for the spell when picking it, and now displaying that face might make players without 5e knowlege overlook that spell. Things like range, durations, radius etc would be nice. There could be an option for players to show a lot of tooltips or shorter tooltips.
Food feels kind of broken, it just heals for a lot more then you'd expect, almost as good as potions. With potions being bonus action you run the risk of combat getting overly reliant of stacking tons of potions in your inventory so you have extra life every turn. And with healing seemingly very cheap, I imagine this strategy will be quite easy to employ and make battles trivial. I havent had to use potions in combat, maybe there is a cooldown on using them, otherwise, that might be an idea.
One short rest per long rest seems to be what this game allows, I'm worried this is a big nerf to classes that is more reliant on short rest. Allowing short rests whenever a player feels like it sound kind of broken however as well. Possible fixes could be special areas or events when exploring a dungeon that offers a short rest as a one time deal for the day, like you stumble apon a room with a refreshing magical fountain or something that invigoraties the party (short rest.). This would help the short rest reliant classes a lot. (Now, I have no idea if the game punishes taking to many long rests, but I have assumed so based on what the character are talking about, things seems very urgent. If that's not the case, then long rest spamming might be a thing.(I hope not.))
Upcasting spells seems to not be a thing, I belive this is a big mistake, I hope it get implemented. Not being able to upcast is very odd. (This might be a bug for me.)
Magic items felt surprisingly cheap to me, but im fine with that. I like that random gear can give minor bonuses to strength checks or whatever.
And lastly, the spells look very cool, I really enjoy the eldritch blast animation and scorching ray for example, I'm sure there are many more. The game looks amazing generally, some odd facial exprassions sometimes, but whatever. Interesting characters. Nice envoiurments, not going into spoilers, but I enjoyed some of the more unexpected encounters i've had so far a lot. I think this is a fantastic start, and I'm sure big improvements are to come! Thanks you Larian.