Didn't play Net High. Nor plan to do, since I can't japonês.
Grand Kingdom demo seems legit. Played just the first mission for now (move around a map fighting enemies until you reach the goal panel). The map movement is just like GKH, with the enemies moving whenever you move (or press X to spend a move and stay on the same place). You have a limited number of moves each mission, and I guess you fail if you spend it all before reaching the goal point.
Battle is well different from GKH. Where in the latter you placed your units on a grid and just attacked in turns, here you can (and will) move your units back and forth and between three lanes. Flanking and back attacking is possible this way. Moving is limited by an AP bar, like Valkyria Chronicles - you can't even cancel your actions, so if you move wrong you can't redo it (or I didn't find how to - pressing X just cancels the unit's turn).
Usually, characters have an attack with unlimited uses (set to Circle) and some with limited uses per mission. Attacking costs AP too, but I'm not sure if it's a separated AP bar from the one used in moving (it probably is). Fighter can attack multiple times, combo'ing, and will automatically assumed a Guard stance after his turn. Guarding attacks uses AP, so if you spend it all attacking you won't be able to block much stuff.
He doesn't have a limited use attack, just normal attack and Guard.
Archer and Witch have long ranged attacks. Range is fixed, to you need to adjust your distance. There's friendly fire too, to it's not save to use them agains an enemy near your fighter.
Their common (circle) attacks target an area that would fit around 4 enemies if justaposed. A cursor will move on the ground inside that area (from left to right), and the attack will land whenever the cursor is when you press circle. After the first attack you have a limited time to attack again and combo. If you stay a few seconds without attacking the turn will end (and unspent AP will be saved for the nexr turn).
Archer's limited use attack is a strong charged shot that hits the first unit in the lane (including your own units). Witch's limited attack is a lightining bolt that hits everyone in the lane (again, including allie).
The cleric can throw a potion to damage enemies, throw healing potions to heal allies and drop healing bags for other units to pick up and heal.
Didn't see anything about choosing a Kingdom to fight for and such yet. For now, I enjoyed the combat more than GKH. Need to find some more time to play the rest of the demo. For now, I'd be most pleased to see this coming here, but let's wait for impressions for the full thing (Parakeetman pls).
And there's some demo footage on Youtube already, so go check those if you must
