i play mostly paper magic our group is pretty casual, but i found the deck really good against non-creature based strategies. i can usually pull a 3rd or 4th turn win consistently. i used to run fling when i had more souleaters, but then i realized i never wanted to draw more than 1 at a time so i cut them from the deck. i decided to stick with only 1 cc spells to keep the curve super low.
I also run a kiln fiend deck and I think the right strategy is to use assault strobe to steal as many 3rd turn wins as possible. You just gotta run more threats as a backup plan in case you don't draw your kiln fiend.
I think it's a bad idea to run board sweepers. With almost everyone running fetches and shock lands it's much better to just race them. If zoo is really gonna be big then just run grim lavamancer and searing blaze. Since there's no real replacement for sulfuric vortex, i think figure of destiny is worth playing for the constant damage.
i haven't seen much discussion for teetering peaks. it could be alright as a 2 of alongside both spark and hellspark elementals, bringing them to near ball lightning power. it could also boost goblin guide and keldon marauders in a creature heavy build, and can be sacrificed to shard volley in place of a mountain. you'll have to cut down on price of progresses though
In some ways Ensnaring bridge feels redundant with Liliana or Pyroclasm. You'll probably be dropping one of these ASAP to slow your opponent down.
Also, why not just run 4 of mutagenic growth, apostles blessing and assault strobe? forked bolts just seem weaker
3 Vault skirge
4 Kiln fiend
4 Porcelain legionnaire
3 Bloodcrazed neonate
2 Keldon marauders
1 Immolating souleater
2 Bonesplitter
4 Lightningbolt
4 Burst lightning
4 Assault strobe
4 Apostle's blessing
3 Mutagenic growth
2 Gitaxian probe
16 Mountain
4 Teetering peaks
My deck plays much like a sligh/burn carrying an instant win combo in kiln fiend/assault strobe/apostle's blessing/lightningbolt.