2k list - help me improve it

I just played my 1st game with the codex against a Imperium player who run RavenGuard (3x6 aggresors, 3 tacticals, cpt, lt) + Imperial GUard (Leman comm, 5xBasilisk)

After 2nd turn he did conciede as I killed 3/4 of his army losing a Ravager, Mandrakes and few Wounds on boats.
To be fair I got 1st turn...

Would like to hear your feedback on my list:

BLACK HEART SPEARHEAD 449
HQ:Archon, Agonizer, WT, Living Muse = 74
HEAVY SUPPORT1: Ravager 3DC = 125
HEAVY SUPPORT2: Ravager 3DC  = 125
HEAVY SUPPORT3: Ravager 3DC  = 125

FLAYED SKULLS BATALLION 964

HQ1:Archon, Agonizer, Blaster = 91
HQ2:Archon, Agonizer, Blaster = 91

TROOP1:5x Warriors, Blaster = 47
Raider, DL, SR = 90
142

TROOP2:10x Warriors, 2x Blaster, Dark Lance = 114
Raider, DL, SR = 95
209

TROOP3:10x Warriors, 2x Blaster, Dark Lance = 114
Raider, DL, SR = 95
209

ELITE:Mandrakes (10) = 160pts


RED GRIEF OUTRIDER 619
HQ: Succubus, Agoniser 54pts
FA1: Reavers (9), 3 blasters, agoniser 222pts
FA2: Scourge 60pts
FA3: Scourge, 4 blasters 128pts
FLYER1: Voidraven bomber 155pts

All the HQ started in the Raider with 5 guys
Voidraven is cult to enable using the "shoot again" 'gem

I like very much. Probably would swap the Bomber for a Fighter as I prefer the model, but that's just modelling wise.

What about the mandrakes? were they worth it?
I don't really like the models, but with some conversions, I might take some, dunno yet.

With your weapon loadout, I'm not surprise you annihilated him  (Aggressors don't like dissies at all lol), with 1st turn; still, with -1 to hit, at turn2? You came right next to him or what?

Well the Mandrakes did not do anything as the aggresors shoot them to death as they came on from DS with a stratagem (and I forgot to use the cancelling one). I loved them in the index - now they got cheaper and better. I hope I will be able to test them in future games

He used the Raven Guard deployment gem to put the aggresors closer to my line to have them in range 1st turn and shoot twice. I deepstriked my Ravagers close to him... and you know the rest