I installed it and there is an update button that takes me to an update page to download the 1.34. When I install the new version there is no more update button. I guess gog is not the latest version?

You are right. The latest version (V 1.3.4) is currently (as of this post) only available from the developer. It fixes a bug where any attempt at recruiting is always successful.

I have noticed unusual battling behavior, even with the newest version. The only battles that occur seem to be the ones I initiate. My lords are never attacked.

Let me know if you have that problem too.

It's weird how difficult it is to get a fully working conversion of Doomdark's Revenge. I tried a Game Boy version using emulator that was also full of weird bugs; the lords would all end up at the edges of the map, for example.

The original ZX Spectrum version seems to be bug free. You can choose to attack enemy lords but even if several hours remain of the day at the time you attack, there will be no combat if the enemy lord(s) choose to move, which kind of ruins the strategic part of the game. But I'm not sure if it's a bug or just questionable design.

IMO Revenge is not a war game.

The player needs to recruit a lot (best if all but Shareth) lords. But only lords taht are alone can be recruited, so try
to get them alone and do not let your own alone. If attacked try to retreat a little so that opponents split. And the goal
is not to kill them in battle, but to recruit.

Learn who can recruit whom.

Again IMO the easyest way is to have Luxor protected by Barbarians, Tarithel recvruit Fey, then Dwarves and Rorthron
recruit Barbarians, then Giants.

Try to guess the path ice lords must take and be prepared to recruit as many as possible.

At the end ice lords must escort Tarithel so that she recruits Morkin.

The easiest way to win is to park Luxor down a tunnel and wait for Shareth to get killed.
But that's no fun.
Personally I think the game is more fun if you treat it as a wargame and set you own goals, like for example recruiting only Good lords, or only Fey, for example.

Just recalled a definite ZX Spectrum bug - when fighting soldiers get more invigorated instead of tired. Anyone know if this was fixed in the remake?

Everybody, but icelords and their troops, can become tired by the "fog".

And walking also makes fadige, while not walking gives +1 point of health. So, yes, if combat but no walk they become +invigorated (no idea if it was a bug or not).

I'm not sure if this was a bug or a design problem. One of the issues with the AI in Revenge is that, in battle, not everybody actually fights. So if you place a couple of lords into battle, only 1 lord and his army might fight. As soldiers and lords get more invigorated every day, it can seem like they have gained an increase while fighting. But the actual problem is that they didn't fight. GoG are always running a little behind on updates. This is partly mine and their problem. I usually update them a little later than all the other versions, just in case there are problems with the updates. And it takes a little time for them to process updates.

They are currently 1.3.3, I have just sent them 1.3.6 The original is definitely not bug free! :) And some of the expected behaviour in the original is actually the result of bugs, which makes remakes a little more difficult. Lords of Midnight is a much tighter product.

That said, some of the issues with remaking is fully understanding what the code is doing, and I must admit, I have had a few issues there with this version. I think however, I now pretty much have it, thanks in a large amount, to the people playing it.