What is your opinion of melee combat in Op4?

If you give the players no other options, they will eventually get used to using only melee.

Just be careful about the difficulty ramp. Warm them up with some headcrabs and breakables first and slowly increase the encounter difficulty instead of dropping the player directly into an arena with several gonomes and bullsquids. Let them become comfortable with it before challenging them, so to speak.

If the enemies have ranged attacks, give the player plenty of cover so they don't end up feeling defenceless (which in turn is experienced as unfair and difficult by the player).

That's all good advice, thank you. Unfortunately I start them out with a gonarch (that they can run from). But I suppose I will not proceed with my plan to put them up against a voltigore shortly afterwards :-/

As long as you make it clear they have to flee from the Gonarch and not engage in combat with it, it should be fine 🙂

They have the option to flee, and also plenty of ways to avoid confrontation as they figure out how to flee. Also, two to 4 direct hits to the sack gibs the thing and I've loaded them up on armor and health is available.

I guess I won't know if it's too difficult until I get it playtested.