Here's where Hippowdon vs Talonflame likely takes place on the map.
Other damage ranges in the trailer:
Wild Flaaffy's ThunderShock does 4 damage to Chikorita. This is pretty much expected from a random wild without perfect IVs.
Lvl 15 0 SpA Flaaffy Thunder Shock vs. Lvl 15 0 HP / 0 SpD Chikorita: 5-6 (11.6 - 13.9%) -- possible 8HKO
Totodile does about more than half to Tepig with Water Gun. This one I could see if the enemy was set to be a bit weaker.
Lvl 10 0 SpA Totodile Water Gun vs. Lvl 10 0 HP / 0 SpD Tepig: 14-18 (38.8 - 50%) -- 0.4% chance to 2HKO
Lvl 10 0 SpA Totodile Water Gun vs. Lvl 10 0 HP 15 IVs / 0 SpD 15 IVs Tepig: 14-20 (41.1 - 58.8%) -- 88.7% chance to 2HKO
Mega Absol OHKOes a trainer's Altaria with Stone Edge. This one is the most questionable compared to a standard calc with no crit message, but there's always the possibility of unknown investment and the additional icon beside each move while mega evolved might imply some other buff involved.
Lvl 57 0 Atk Absol-Mega Stone Edge vs. Lvl 60 0 HP / 0 Def Altaria: 122-144 (68.5 - 80.8%) -- guaranteed 2HKO
More thoughts on the battle system and moves:
Currently I am kind of interested in Chikorita and possibly showing a more unique style as a projectile/support focused mon to differentiate itself. The initial trailer shows Leafage in action and the extended look shows Razor Leaf. My guess is that Leafage is more of a tracking projectile while Razor Leaf hits an extended area in front like Flamethrower. Chikorita's moveset also shows Disarming Voice (usually a perfect-accuracy spread move) and Leech Seed which could be interesting for damage over time.
Flaaffy's Thunder Shock doesn't quite seem to be quite the same as either projectile from what I can tell, as it animates the shock kind of spawns on top of Chikorita directly.
Totodile has Tackle/Water Gun/Leer/Bite. Notably Scratch seems to have been replaced with the all-purpose Tackle yet again, though I guess in this setting Scratch would be a similar close range attack like Bite while Tackle could be a dash. Water Gun seems to track a bit even while Tepig is moving.
The enemy Tepig uses Rollout in the extended trailer and Flame Wheel in the initial trailer. In both Totodile seems to dodge it by following the trainer's movements. The rival seems to have 2 mons as seen in the top of the screen. I picture Tepig will be mostly melee focused, though I also picture that for Totodile so that's why I'm interested in how Chikorita will lean.
Protect seems to be pretty viable to react to an attack's startup with, even from like point blank range, though I imagine Moonblast also takes a while to proc.
There seems to be a run/forfeit button with minus shown in the Lucario vs Spritzee battle.
Other moves that exist and my thoughts:
In the initial trailer, Mega Lucario seems to use Aura Sphere, Gardevoir shoots some purple ball that looks like the other Moonblast, and Mega Charizard X does a fire dash that seems like Flare Blitz.
Amnesia/Roar/Stealth Rock/Heavy Slam on Hippowdon. Aside from Stealth Rock, these did not appear in Arceus. Haven't seen much of what buffs look like. Roar is kind of an interesting one to adapt and I feel like it might be a more generic stun or something. As mentioned, Stealth Rock seems to act as a damaging area on the field and doesn't quite disappear even when Talonflame runs into it with Flame Wheel and loses its HP (but does not faint).
Air Slash/Bug Buzz/Hurricane/Safeguard on Vivillon. Safeguard implies the existence of status effects or an equivalent and support moves still being a thing for the party.
Onix has Screech/Rock Slide/Sand Tomb/Dig and shows Rock Slide as targeting from above. Dig is kind of an interesting one too, PLA adapted Shadow Force as adding obscured/increasing evasion but I can imagine it getting kind of creative here. Sand Tomb I can see as a lasting damage area like Stealth Rock, though unlike Stealth Rock it does have a type effectiveness icon so maybe it could restrict movements. The enemy Pyroar uses Flamethrower a couple times, it lasts in front of it.
Mega Absol has Night Slash/Shadow Claw/Air Slash/Stone Edge, Stone Edge seems to be a pretty fast close range thing from the ground.
Charizard has Fire Spin/Flamethrower/Slash/Outrage, and we actually see a notification box that it mega evolved. Outrage seems very vertical to me. Fire Spin also has a type effectiveness icon, but I could also see it as being a trap type move.
Kangaskhan has Double-Edge/Power-Up Punch/Crunch/Bulldoze, and as mentioned Bulldoze is an AOE.
In the initial trailer the trainer does a dodge roll away from Pyroar's Flamethrower. This made me wonder how much the trainer affects things. Could you just hit the other trainer in a battle while they're on the field? Much to consider.
Overall looking at it closer I wonder how in control the combat will actually feel and how far you can engage with it when you're primarily controlling the trainer still, but so far Chikorita has still piqued my interest in terms of standing out with a niche. People might find it more intuitive to deal with than PLA action speed, maybe, and the battle messages being passive is at least already faster than having to progress through them. On the other hand, I've seen some talk about PVP already and I just see that as ending up like Sparking Zero but without the patches.
Mon swapping seems to be done with the d-pad, or at least represented with down/up arrows.
Also, the website doesn't list abilities for the starters so far, like PLA, which is a potential point against them.