The game is fun so far, but combat seems clunky in some areas and I would like to list them below to see if other people agree:

1) Attacks are missing too often (Player and enemies too)

In the mission "Search the Cellar" I had to fight enemies with 18 AC and I had two whole rounds in which I couldn't hit any of them nor they could hit me, so it
was just missed attack after missed attack. Without even adding that I had 5 Critical misses in just one fight, if we leave it all just to the numbers it can create unrealistic absurd results that break immersion (without a DM to soften things up). Maybe some tweaking needed?

2) Melee could use a buff

Opportunity areas are too small, taking into account that on a D&D game a melee character controls a 15ft wide area with the opportunity attack. That is useful for strategy and
crowd control. Side note: I loved the addition of Cleave for big weapons adding the chance of AOE for melee, but using it once every short rest is too little.

3) Disengage should be an action

Maybe jumping should activate opportunity attacks, or we could have jump separate from disengage, otherwise melee is just too nerfed and all the effort you had to make to move across the battlefield towards an enemy is negated when they can easily hit you and run away in the same turn.

4) AI is predictable

The AI is targeting almost always the weaker character, that is predictable and sometimes it goes into a loop where you heal that character, they hit him, you heal it back again and so on. A more realistic battle would be for each "AI player" to target their most immediate threat, for example sometimes a goblin archer would ignore the fighter that is about to chop them in half and just shoot an arrow to some other enemy all across the map.

That is all I can think for now but it would be great to read what others have to say or if they want to add things to the list. Overall the game looks really promising!