Sorry but I don't really understand the point of much of this subclass, it's just stuff you could do as a warlock normally. Just take Grasp of Hadar, Devil's Sight and the Hunger of Hadar spell and you've basically got the same thing as this subclass.

Likewise some of the spells on the spell list either don't upcast well (absorb elements, blind/deaf/freedom of movement) or are already warlock spells (Blink, False Life), so are kind of wasted.  

Some of the other features are counter intuitive as well, what does Adv on saves have to do with hunger? What does healing conditions have to do with hunger?

Finally, Death Ward should never be available to Warlocks because of their short rest casting feature means they can put it on every member of the party constantly at practically no cost.

GOO is only the lazy choice here if you refuse to make any effort to add flavor of your own. As Agile says above, you can take most of these elements already and tie all those together to describe Hadar's powers. Subclasses like this are not intended to feel generic, they are intended to be flexible templates that you make your own through roleplay.

All that being said, if you're really into the features here this seems fine to use aside from the issues Agile pointed out with the spell list.

Quote from Agilemind >>

Sorry but I don't really understand the point of much of this subclass, it's just stuff you could do as a warlock normally. Just take Grasp of Hadar, Devil's Sight and the Hunger of Hadar spell and you've basically got the same thing as this subclass.

Likewise some of the spells on the spell list either don't upcast well (absorb elements, blind/deaf/freedom of movement) or are already warlock spells (Blink, False Life), so are kind of wasted.  

Some of the other features are counter intuitive as well, what does Adv on saves have to do with hunger? What does healing conditions have to do with hunger?

Finally, Death Ward should never be available to Warlocks because of their short rest casting feature means they can put it on every member of the party constantly at practically no cost.

 Death Ward is a spell for Undying and Undead Warlock’s. 

I wanted to focus on the spells which Hadar bestowed to its followers and adjusting how they can be used by its warlocks. Also, False Life and Blink are not warlock spells, they are only Wizard and Sorcerer spells. Sometimes spells are not just about upcasting and since they are just available to the warlock, they do not have to take them. They just fit the theme set by reading the background and tooling around how Hadar is presented in the cannon of DnD.

To help for those that are not familiar with Hadar's lore or just don't want to read the link, Hadar is an ancient Far Realm-infested star of Realmspace. Its primary attributes are that it was a red giant that collapsed and is now a red dwarf star struggling to absorb any energy to stay alive and feed its core. It is also not stationary and tends to shift and move in unpredictable patterns. The infested star sends out its minions to absorb energies which Hadar uses to keep alive and not burn out. It is a star and although it is no longer strong enough to heat the cold stretches of space around it as it did when it was a red giant, it is still a burning star capable of generating vast heat. Hadar's hunger is its desperate attempt to not burn out into annihilation.

I feel a bit mixed by this... on the one hand, I think this does a pretty good job of capturing the unique feel of a creature like Hadar and focuses on the kind of powers I feel like Hadar might offer, based on existing spells and such. On the other hand, this subclass looks pretty uh... boring. I think the fact that you could very nearly build this same subclass just with some spell and invocation choices. Unfortunately, I don't really have many alternative ideas... I just generally dislike subclasses which have class features that basically just boost a single spell (like this does with Hunger of Hadar). I generally have the attitude of, if I want that spell, I'll just take it on my own. I want subclass features that do things that can't be accomplished with spells. I do wonder if you could instead change this to be something like what Evocation Wizards get... instead of just being functionally immune to one specific AOE spell, I'd enjoy it more if this just gave you general immunity to any of your own spells.

I haven't been doing this so often b/c lots of people just reject suggestions, but in case you are interested in alternative options here are some:

Some Possible 1st level features (note including all of these is probably OP these are just ideas to stimulate your creativity).

Gravitational Grasp : When you hit a creature with a spell attack roll or a creature fails a saving throw against your spell you can pull them 10 ft closer to you. A creature can only be affected by this feature once per turn.

Gravitational Tether : As a bonus action you can magically tether one creature that you can see within 30 ft of you. It's movement speed is halved as long as this tether is in place. This tether last for 1 minute or until you use this feature to tether a different creature.

Absorption : When you reduce a creature to 0 hp you gain temporary hit points equal to your warlock level.

Some Possible 6th level features:

Collapsing Star : As a bonus action you can change your size to be Small or Large or revert to your normal size, while you are Small you had disadvantage on Strength checks and saving throws, while you are Large you have advantage on Strength checks and saving throws.

Dwindling Light : As a bonus action you can emit bright light in a 10 ft radius around you, creatures that start their turn in this area take fire damage equal to your Charisma modifier. This effect lasts for 1 minute, and once you use this feature you cannot use it again until you finish a short or long rest.

Erratic Movement : When you expend a spell slot to cast a warlock spell, you can move up to your movement speed immediately after casting the spell (no action required).

Some Possible 10th level features:

Improved Gravitational Grasp : The first creature you target with your Gravitational Grasp must make a Strength saving throw against your spell DC or their are unable to willing move away from you until the end of their next turn.

Improved Gravitational Tether : At the start of each of your turns you can move the creature affected by your gravitational tether horizontally up to 20 ft in a direction of your choice.

Elemental Absorption : When you take cold, fire, lightning, thunder, necrotic, or force damage you can use your reaction to grant yourself immunity to that instance of damage. Once you use this feature you can't use it again until you finish a short or long rest.

Some Possible 14th level features: 

Insatiable Hunger : When you are targeted by a spell of 5th level or lower, you can use your reaction to instantly end the spell prior to being affected by it, and you can regain one expended spellslot of 5th level or lower. Once you use this ability you cannot use it again until you finish a short or long rest.

Core of a Star : You gain resistance to fire, necrotic and radiant damage. When you cast a spell that deals any of these damage types you add your charisma bonus to the damage.

Eldritch Abomination : As an action you can grow 4 terrifying tentacles from your body, they last for 1 hour or until you choose to end them (no action required). Each tentacle can be used as an additional arm and hold and use any one-handed weapon with the light property, a spellcasting focus, or item (excludes shields) weighing no more than 10 lbs or for grappling another creature. In addition, you have advantage on Intimidation checks and disadvantage on Persuasion checks while your tentacles are manifested. Once you use this feature you cannot use it again until you finish a short or long rest.

Some Possible 14th level features: 

Thank you Agilemind for breaking me and my DM from focusing on the spell and giving us some cooler ideas. We think we have a good battlefield control build that still fits the feeling and vibe of Hadar. Adjusted the spell list a bit as well.

1 - Touch of Hadar
When you hit a creature with a spell attack roll or a creature fails a saving throw against your spell you can pull them 10 ft closer to you. A creature can only be affected by this feature once per turn.
1 - Erratic Movement
When you expend a spell slot to cast a warlock spell, you can move up to 10 ft immediately after casting the spell. You are still prone to attacks of opportunity and the conditions of the area such as difficult terrain.

6 - Sapping Tether
As a bonus action you can magically tether one creature that you can see within 30 ft of you. It's movement speed is halved and it must make a strength ability check against your spell DC or be are unable to move away from you. This tether last for 1 minute or until the creature takes an action to break free with a successful strength saving throw against the your spell DC.

10 - Insufferable Polyphagia
Hadar’s immense hunger infuses your very soul and inures you against other desires. You are immune to the Charmed and Frightened conditions.

14 - The Unquenchable Appetite of Hadar
When a target is damaged by a spell cast by the warlock, some of the life force is transferred as health equal to the warlock’s proficiency bonus. This transfer can also end either the blinded, deafened, paralyzed, or poisoned conditions instead of transferring health to the warlock. This transfer can only be applied once in a round.

Alternate Spells:
1 Absorb Elements, False Life
2 Blindness/Deafness, Kinetic Jaunt
3 Blink, Nondetection
4 Death Ward, Freedom of Movement
5 Immolation, Commune

Nice! That looks like a fun subclass!

Thanks for the input Agilemind. We always put small tweaks on other subclasses to meet the characters a little better, but this one idea did not have anything like it in the other subclasses.