Thanks for the feedback! I'd definitely like to address a lot in a future version. Answers to the questions:
Yeah, equipment is armor and also gives you one Pokemon type each. The damage formula, which we should really indicate somewhere, is (attack level + 1) * 4 * (multiplier based on type effectiveness) / (defense level + 1). Attack/defense levels are based on item levels, and also ranged attacks do half damage. All attacks deal at least one damage.
And yep, the same two items always produce the same result, at least in the same playthrough.