Death's Gambit

• A Strength build is recommended for a first playthrough. Almost all shields have a Strength requirement, so you're going to need to level Strength anyway if you want to use a decent shield. There's also a wider variety of Strength-based weapons than Finesse-based ones.

• You will almost certainly want a good shield, because blocking and countering is extremely powerful. Learn how to do it early and you can trivialize a lot of bosses.

• Don't worry about the Will stat.

• Don't upgrade your initial equipment unless you're struggling with the early game; equipment you find later is superior in every way.

• The heal you get from parries only triggers a few times per rest; after that parries won't heal anything. So don't think you can use parries to heal yourself indefinitely.

• Don't be afraid to sacrifice your phoenix plumes for the damage boost. If you're aggressive, this can let you end fights so fast you won't need to heal in the first place.

• Those narrow gaps can only be passed with a mobility upgrade unlocked at the very end of the game. Take note of their locations, but don't expect to get what's on the other side for a long time.

• NPCs recruited to Central Sanctuary will die as the game progresses. It's not obvious, but they're actually being killed by Bast (the lizard-man in the center of the area); if you don't want them to die, kill him after purchasing everything you want from him.
  However, the game is beatable even if you don't do this, and I'd actually recommend letting it happen on your first playthrough for atmospheric reasons.