Gameplay-wise, I would say:
NOVICE: basic hand motion, "fire and forget"
Pull - simple telekinesis, akin to basic levitation.
Throw - simple telekinesis, essentially a push from afar.
Slam - a combination of Pull and Throw, basically the former in an upward direction followed by the latter in a downward direction.
Lash - a unique take on the basic telekinesis; a generally horizontal force applied to destabilize.
INTERMEDIATE: concentrated thought, deliberate intent
Warp - a projectile that continues to damage an enemy, must be composed before release but once launched doesn't need to be "maintained".
Shockwave - a self-detonating pulse that continues to travel after initial blast, but doesn't change direction.
Barrier - a defense around the body that reduces harm inflicted; must be maintained, but it does one thing and one thing only, therefore simple to apply.
Stasis - a blend of Barrier and Pull, in that it reduces damage but also renders immobile, but not quite to the extent of either.
Reave - targets the mind, USING the mind, to benefit the body; must travel and translate across different physiology, but is a "switch" ability, you either turn it on or it is off.
Warp Ammo - altering the state of ammo to have biotic effects; simple in concept, but has to be constantly applied.
DIFFICULT: utmost dedication, intense focus
Biotic Charge - surround yourself with the same energies that propel starships at FTL speeds, propelling yourself at said FTL speeds; often phasing entirely through solid objects, both living and not.
- To clarify, this is the same energy that can rip titanium/tungsten composite like tissue paper, and you are literally glowing with the stuff around your comparatively fragile, organic body.
Nova - gathering the same energies from Biotic Charge and dispersing them in a 360 degree radius around yourself, draining your barrier and producing collateral damage.
- To clarify, you somehow need to do this WITHOUT any sort of backlash, otherwise you are detonating your own cells.
Dark Channel - almost an advanced Warp; travels between targets and must identify whether friend or foe.
Singularity - bring into existence one of the least understood universal phenomenons at will.
- To clarify, black holes.
Flare - expend every iota of mental power into a single manifestation of raw cosmic power.
- To clarify, supernovas.
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Lore-wise, it's harder to pin down, because biotics manifest differently among different individuals, and at different "power" levels. I attempted to use intuitive thinking in my description of the powers.