Risk of Rain Vanilla Miner

The Miner's unlock is a bit unusual: that time I fought the 'Direseeker' in the Magma Barracks and killed it, with it being hidden off down a path you have to walk through lava to reach? Killing Direseeker is how you unlock the Miner. There's only one version of the Magma Barracks that even can have it, and I'm given to understand it's not actually guaranteed to spawn even if you get that particular map. As such, while you can't possibly unlock the Miner before, say, the Bandit, how early or late you unlock him is primarily determined by how inquisitive and lucky you are. If you tend to explore nooks and crannies, then you'll probably unlock the Miner the first time you get a Magma Barracks that has Direseeker in it. If you're not inquisitive... you might never unlock him without getting frustrated and outright looking up how to unlock him.

The Miner's four moves are...

Crush

Hits all enemies around the Miner for 140% base damage. No cooldown.

Drill Charge

Pressing and holding the button starts building a gauge. While the gauge is building, the Miner is unable to use other moves, but is free to move about and jump. When either the gauge reaches full after 2 seconds or after the player releases the button, the Miner charges forward a fixed distance (Gauge charge does not affect it) for potentially up to 600% base damage (Based on how long charging has happened) to all enemies he passes through, with substantial knockback applied if possible. During said charge forward, and for a brief period afterward, the Miner is invincible. 8 second cooldown.

Backblast

The Miner instantly dashes backwards, hitting all enemies a modest distance out in the direction he went for 200% base damage and attempting to stun them. The Miner is invulnerable during the dash, and for a brief period afterward. 5 second cooldown.

To The Stars

The Miner performs a full additional jump, even if in mid-air, and at the apex three projectiles instantly impact the ground below him, separated so that there's no overlap. These projectiles do 180% base damage apiece to targets caught within them, and can potentially have all three hit against larger targets. 5 second cooldown.

And since I got double Ancient Scepters, the Ancient Scepter (There's no stacking effect for it) turns To The Stars into...

Starbound

As per To The Stars, except it generates 5 such projectiles, widening its blast radius, and it can inflict Stun.

An annoying fiddly detail of the Miner's; like the Sniper's Steady Aim, Drill Charge decides its damage based on how long you charged, but attack speed modifiers speed up how quickly the gauge fills, thus lowering its maximum damage. Unlike the Sniper, the Miner gains attack speed per level, meaning that it's completely unavoidable that Drill Charge will get weaker and weaker as you progress. On the plus side, Drill Charge is not a centerpiece of the Miner's design in the way Steady Aim is for the Sniper, and it seems to start at about 200% damage if you just tap the button, plus you can keep moving while using it and even if its damage ever did end up complete garbage it would still be useful as a mobility enhancer, unlike Steady Aim having no utility outside damage.

The Miner, like CHEF, has some problems from his basic attack being really, really good and his other moves not being as competitive, but nowhere near as bad as CHEF is. Yes, the Miner has a habit of eventually turning into 'bunny hop amid mobs of enemies while continuously swinging with Crush to kill everything', but To The Stars actually delivers enough damage quickly enough while protecting you by keeping you out of the mob that it remains worthwhile, and Drill Charge and Backblast remain useful for keeping yourself alive if things start going badly.

Unlike CHEF, the Miner has a major weakness of just plain sucking against Providence. To The Stars tends to only hit Providence once, for okay damage. Backblast can't stun Providence and only does okay damage. Drill Charge's damage has already taken a noticeable blow since you're probably at least level 17 by the time you reach Providence, and even the base max of 600% isn't that great when you consider it would only be occurring every 10 seconds. Crush puts you right inside Providence's sword range, and while it's amazing at tearing apart mobs and is even okay at killing single tough enemies, Providence is simply way, way too tough and hard-hitting for it to be safe to sit on him while Crushing constantly -and he's too small for bunny-hopping to have the kind of reliable damage output you can get against stuff like Elder Lemurians. 

Ideally, the Miner brings a Drone cloud to speed up fighting Providence and make it a lot safer. Any class benefits from such a Drone cloud, but the Miner is the only class I'd say it's practically mandatory if you want the fight to not take forever.

As it happens, that's not why I ended up grinding as long as I did; the actual reason was that I was trying to get keycards and, once I passed by the Golems hanging out near the boombox, trying to arrange to actually get inside and see what that was about. I'd actually not known about those Golems prior to recording this video. Neat little easter egg. I'd actually forgotten just how crippled the Miner is against Providence until the fight started; I don't like playing the Miner, as he's kind of boring. (This is also why I kept using fully charged Drill Charges for mobility early on; I'd forgotten that charging it doesn't affect its distance) I like the idea of the Miner, he's clearly intended to be an evasive melee combatant who bounces around while delivering damage, but bunny hopping while spamming Crush is simply too good. It gets repetitive, and unlike CHEF it doesn't even feel particularly unique. I could play one of the other melee classes while having a bit more versatile of an experience if I wanted to spend a decent amount of time bunny hopping while spamming my basic attack.

A couple of non-obvious mechanical notes: Crush hits a surprisingly large area around the Miner, much larger than the graphics would lead you to believe, so much so the Miner can hang out at a ledge and be hitting enemies above or below him without issue. Unlike some of the other melee classes' basic attacks, Crush also doesn't force the Miner to move as part of the animation, so simply sticking yourself next to a ledge and holding down the button is a very safe way to kill basically anything that doesn't fly and doesn't understand how to climb ledges. (Or, alternately, doesn't understand how to fall down ledges; Parents are an enemy that can't hop up ledges but can go down them just fine, where Golems have no understanding of verticality)

To The Star's 'projectiles', on the other hand, don't behave how you might expect them. There's no travel time. They don't hurt anything intervening. They just spawn at ground level, no matter how far away that is from your current position, and do damage to enemies caught in the graphics.

Backblast is also painfully un-intuitive, poorly described by the game, and its own visuals compound the issue by throwing in a visual effect in the direction you're jolting away from that's far more prominent than the visual effect behind you. You'd think it hits enemies in front of you while kicking you away from them. No, it kicks you away from your current facing and catches enemies you were blasting toward. The intent is probably that you fire off Drill Charge and land on the other side of or in the middle of enemies and then immediately use Backblast, bouncing back out of them while dealing damage and stunning them.

The Miner isn't as poorly balanced as CHEF is, but he's probably worse-designed.

On the more positive end, the Miner is another of those characters who is fairly good at leveraging on-hit effects, thanks to his high attack rate on his basic attack and ability to toss in other attacks without much opportunity cost. (Even Drill Charge, if you're willing to just tap the button and accept the meh damage)