The game is meant to be multiplayer, but the community has largely died off, sadly.
And while the second Kohan game (KKoW) is a bit more forgiving than KIS/KAG, it certainly isn't a more traditional RTS. It *looks* like War3, but it certainly doesn't play like it.
One of the main differences between the two games is that KIS/KAG allows you to settle new towns anywhere, while KKoW forces you to use predefined settlespots. Might not seem like much of a difference to people not familiar with the series, but that was one of the dividing points of the community.
The campaigns for both games are rather meh and, at least for KKoW, the campaign actually can hinder your development as a player due to bad habits you develop since the campaign never really mimics real multiplayer situations. For an actual challenge, play some of the SAI's on hard or impossible in a 1v1 skirmish.
Some novel/memorable features:
Of the five resources, only gold accumulates. The other four (Stone, wood, iron, mana) are used purely for upkeep. If you're producing excess mana, for instance, it's completely wasted. If you fall up short in production, for each mana in the red you are, you lose 5 gold per minute.
Units are formed up into customizable squads that have bonuses based upon different types of units assigned to'em (In KKoW, for instance, if you stick pikemen in the flank slot, the entire company will get cav foe (+5 attack vs cavalry)).
Resupplying troops only takes time, not gold. This doesn't mean you should pointlessly engage your troops, however, as if you lose a battle badly enough (Even if you don't lose a single company), you're completely fucked...provided your opponent realizes this and presses his advantage.
Company experience is huge.
As is flanking (Even though there aren't any direct bonuses for flanking ala TW series). The difference between a competent player and a good one is their ability to flank.
No micromanagement akin to SC/WC3/etc. Once engaged, your troops are out of your control beyond retreat/rout commands. Which is why there's really only one hotkey that I'd suggest one learn (for KKoW): Alt. It's the hotkey for run/retreat. That's not to say the game is boring/you'll never be overwhelmed...KKoW is probably one of the most tiring games I've played. Multiple fronts. Watching for a flanking force. Cycling out troops so that you don't lose the company. Responding to enemy raiding forces (A small force able to take out a town's militia, but not much more). And so on...
Probably more that I'm missing.
Unfortunately, RTS games don't make for good LP material or I'd do one in an instant.