What are the best upgrades for speeding through the game? Mine would be as follows:

GREAT -Safety Jetpack -Apple -Gem Powered -Gunpowder Blocks -Candle -Youth

GOOD -Gem Attractor -Laser Sight -Blast Module -Gem Sick -Rest in Pieces

OKAY -Popping Gems -Heart Balloon -Drone -Hot Casing -Rocket Jump

WORTHLESS -Knife and Fork -Member's Card -Timeout -Reverse Engineering

What are your thoughts on upgrades in Downwell runs?

For quite a few of the upgrades it kinda depends on where you are and what else you have. These are my general thoughts with speed in mind:

Candle: I'll take this over literally anything else. Candle turns every mistake into an opportunity to go really fast. You can even tank through entire boss phases with this.

Gem Sick: This is good pretty much whenever, but especially at the start when enemy density is a bit low and it's a bit harder to keep up Gem High. I wouldn't pick it for the boss though; even with this you'll lose gem high during the phase transitions

Gem Attractor: This synergises really well with a couple of other upgrades but it's not good on its own, for speedrunning you don't really care about gems for shopping.

Gem Powered: if you have this you don't need Jetpack at all; combined with Gem Attractor you'll never run out of ammo

Popping Gems: This is really good from Aquifer onward, it really helps to deal with the boss' minion spawns as well. pretty garbo early though

Blast Module: This can really help with big clusters of enemies. It's a solid pick basically anywhere, but I don't really like it for the boss

Apple: Whether or not you should take this depends entirely on your health situation. If I'm missing need 3 or 4 hp I'll take it. I'll also take it if it will increase my max HP but bear in mind you don't really need more than 6 and you REALLY don't need more than 7

Youth: Gives you more options later on which is nice, but it does cost you an upgrade. Only get this early, or if you -really- need the health

Safety Jetpack: This is only really useful in the first few stages, where you're actually likely to run out of ammo. I'd only think about getting this for the Caverns and maybe early catacombs

Knife and Fork: This really shines in Aquifer because it's so easy to get to corpses there, it's actually better than trying to get combos. It's basically of no use anywhere else so don't get it unless you're around late catacombs/early aquifer

Gem Attractor: This synergises really well with a couple of other upgrades but it's not good on its own, for speedrunning you don't really care about gems for shopping.

Gem Powered: if you have this you don't need Jetpack at all; combined with Gem Attractor you'll never run out of ammo

Popping Gems: This is really good from Aquifer onward, it really helps to deal with the boss' minion spawns as well. pretty garbo early though

Gunpowder Blocks: the upwards shots are ok, what you want it for is the block clearing. Does nothing in limbo but could save you a couple of seconds clearing the corridor before the boss fight

Drone: Again, having damage above you is really useful later on. This can make Burst, Noppy and Machine Gun pretty viable for the boss. Don't get it in Catacombs, you'll be way more likely to set off the flying skulls

Hot Casing: More damage above is always good for later, this one's hard to use deliberately. It can save you some trouble during the boss but it depends on the weapon you have. It's nice to have but it's not a high priority

Laser Sight: This isn't going to make or break your run but it does make most of the weapons a little safer to use against the boss.

Heart Balloon: This slows you down and it's only good for one hit above you. Not really worth picking up in most cases but I will take it if I need some defense against the boss minions.

Timeout: Anything that touches the bubble dies but it's not really onscreen long enough to be useful. -Maybe- ok for the boss fight??

Reverse Engineering: The last time I took this it turned a laser in the Boss fight into a triple. I can see why people might take it but it's a Big No for me

Rocket Jump: I have never found this to be useful at all. If anything the explosion obscures where you are at the start of the jump.

Rest in Pieces: I've never even taken this one, the only time I can keep track of corpses I'd rather eat them

Member's Card: At most you wanna go to one shop in a run if you think you'll need it. Never take this

Based around a playstyle of never going into side rooms. Best to worst.

MVP

• Blast Module: Stomping is fun. Clears groups of enemies quickly.
• Knife and Fork: A good way to keep up with healing as you won't have any other methods except level transition upgrades. Especially potent in aquifer.

GOOD

• Apple: More HP allows you to be a bit more cavalier. Best when you are either missing a lot of HP (as a clutch save) or have full HP (as a max HP up) - I'll avoid it the rest of the time to save it for a more pressing occasion.
• Safety Jetpack & Gem Powered: if you are trying to avoid hitting things as much as possible, then you won't be resetting your shots, nor should you be going for long combos as bouncing on things slows you down much more than just going around them.
• Youth: Increases your chances of getting one of the items above. Obviously best early game.

DECENT:

• Candle: You should try not to get hit where possible, but if you do might as well damage boost more.
• Gem Attractor: Good for triggering Gem Powered and Popping Gems, although you won't need the gems for upgrades.
• Gunpowder Blocks: Clears the area quickly, especially of the blocks themselves.
• Popping Gems, Hot Casing, Drone: Extra incidental damage.

MEDIOCRE:

• Rocket Jump: Almost never useful. Can clear a sticky situation and help with boss spawns.
• Gem Sick: Temporarily increased weapon damage might help against the boss? I just don't bother.
• Timeout: Can maybe clear a nasty mess if you are getting swarmed.
• Laser Sight: I guess beneficial for some weapons like shotgun, but you will only have non-starter weapons on the boss fight and you should be within range the whole time then.
• Reverse Engineering: You only get extra weapons on the boss fight with this playstyle, and you will probably be too busy/distracted to make wise decisions about switching guns.
• Member's Card: Avoid shops anyway. Wasted upgrade.

ACTIVELY DETRIMENTAL:

• Heart Balloon: Slows you down. If you do get this, trigger it ASAP on each level unless on the boss fight.
• Rest in Pieces: Antisynergy with Knife & Fork