So I'm potentially reaching the end of the first act of my campaign this weekend, and now that we've got the rules for statting npcs, I've been working on the climactic encounter. It also introduces what will hopefully be the first recurring villain - a kasatha soldier with a sort of evil space sheriff vibe - so I want the encounter to be memorable. I don't want to tpk these guys, though, so I was wondering if this would be too much for a level 2 or 3 party (haven't figured out which they'll be here yet. Currently level 2 - they may level up first.
Big boss - CR 4 soldier focused on lots of pistol attacks. Bullet barrage, sharpshot style, and I gave him multiweapon fighting and fusillade because I figured it was an okay tradeoff, challenge-wise, for him focusing on small arms.
2 mooks, CR 1/2 combatants. Shotgun mooks with a couple level 1 grenades. Basically there to do a little chipping to the party's SP before they die and maybe draw a little fire.
1 difficult-to-reach CR2 mechanic. He's got the exocortex, I took away heavy army proficiency and gave him sniper proficiency, and he's set up with a 1d10 sniper rifle that he charges with his overload shot for another 1d6. High accuracy and damage, but I'm going to make total cover available in several spots in the arena.
Party consists of...
Melee solarian. Solar weapon and heavy armor.
Healing mystic.
Exocortex mechanic.
Technomancer.
I guess it also bears mentioning that in this fight, the party is going to have a piece of an artifact. I dont know exactly what it does uet cause I'm still designing it, but it will likely let the solarian achieve full attunement 1 round faster at the cost of not being able to control her zenith revelations (they automatically trigger every other round and target everything im range, and possibly fatigue her), and if the party doesnt kill them all in the dungeon, it will alloe them to control a few akatas.
Yeah that's an easy TPK just waiting to happen. Regardless if they're level 2 or 3, you're throwing four players up against four enemies, one of which would be considered a hard encounter by itself.
Take the mechanic or the two 1/2 mooks out. Giving the players an advantage in action economy will go a long way to helping them not die horribly.
Remember, just like all d20 games, at lower levels die variance is much more significant. Even if your players are tactically perfect (which they never are) a string of bad rolls on their part or good rolls on yours and they're in trouble, even in a normal fight. In a combat as dangerous as you've made bad rolls will absolutely result in a TPK, and that's a very negative experience for the players.
No group ever said "Hey do you remember that villain who was higher level than us with a bunch of mook helpers who killed us even though we made all the right tactical decisions but our rolls were just slightly sub-par? Wasn't that a fun campaign!"
What if I drop the big boss to CR 3? This eould drop his full attack accuracy to +7/+7 and his damage to 1d6+4 (with fusillade he can attack in a cone once per combat - he doesmt carry enough pistoks for a second volley). His AC would go down a few points to 17 or so, and his hp would drop 10 points.
Then the party would basically be fighting this guys, and two mooks with 1d4+2 shotguns that will drop in 1-2 attacks, and the sniper, being in a tower about 100 feet away, acts more like an environmental hazard that an shoot one person for 1d10+1d6+2 eaxh round, but can basically be ignored by sytaying in full cover.
Remember that NPCs aren't built as PCs.
The sniper is a problem unless there is a way to get to him. Say a ladder to climb that he can't see while in his tower?
17 AC is too high for that group. 15 at most, your combat specialists should be hitting on 9-10 and being hit on 11s.