This is definitely not another Killzone: Liberation, as IGN's very crabby review (4.5/10) concluded:
There's certainly room for a tactical isometric shooter, but that game is going to have to be at least half as good as the high water mark set by Killzone: Liberation, and this game doesn't even come close.
So, I'm afraid if you've finished Killzone: Liberation, and have played the downloadable Chapter 5 add-on, then you're better off continuing to wait.
The sad thing is, Guerrilla said in their forums that they've already put away their PSP kits and focused all their resources on their PS3 Killzone game.
But, my own thoughts? I'm not a reviewer, and I have a weakness sometimes for games that get trashed (my disclaimer).
I was wrong about the character models being larger. They are maybe a teeny bit larger, and in certain situations where the camera view zooms in, the character models basically scale up in size. And the viewpoint is a bit more vertical so as to let you see into the next room up to a certain point.
Once you go through the training missions, the controls aren't so hard to figure out, but if you just read the manual, they're quite intimidating.
Rather than have you manually aim, you press and hold the L button -- this maps up to all 4 of the circular buttons to any targets in sight. Tab the appropriate button, and then you are locked on that target (i.e., even if you move around, you'll remain aimed at that target you locked in on).
The R button is more of an interaction cursor, something like the mouse cursor in SWAT 3/4. Point out a door with it to get the appropriate squad commands, point at a complaying civvy to give restraining orders etc. There are a few options for automating things, like the interrogation of each civvy or terrorist. You can also set the two squadmates to "auto," " Lethal only" and "Less than lethal." I think even in LTF, I've seen them nail a terrorist with lethal weaponry so I guess they retain some autonomy. To some extent, the AI squaddies are too good -- sometimes I can't get a shot in.
[I know the reviewer complains the AI is awful -- there are some situations where environmental obstructions seem to to block their ability to get an accurate shot in].
While the controls all work OK, I find it a bit too easy to get mixed up. Given the fairly deliberate pace, you generally have time to get things in order (at least on Normal skill). I agree with the reviewer the "fire from cover" mechanic is clumsy and not terribly useful (it looks cool, it doesn't "play" cool in that regard).
The mission maps are pretty long. Start button pulls up a HUD, including a decent 3-D map of the level with cleared areas marked.
Cutscenes are a mix of some somewhat cheesy 3-D render cinematics, and some in-game graphics.
Sound is good, great even. Lots of digitized voices, and the weapons sound OK. Music can be a bit grating but you can adjust it in said HUD screen.
And the game is just sluggish. I guess that's on purpose to get a tactical "feel," but when you laugh out loud at how slow they look when in "sprint" mode, something's amiss.
So, I would probably caution anyone interested in this to try to rent it first if you can. If it doesn't do it for ya, perhaps the upcoming SOCOM: Tactical Strike (which isn't isometric, but seems like it is shaping up better as a tactical squaddie game) will hit the mark better.