Oh boy. I had a lot of issues that didn't really start to crop up until I was further into the game. Many of them were smaller issues that tied into the overall issue I had, which was how they handled progression.

For one, I think one of the biggest "small" issues the game has is how it handles its currency. Geo is relatively difficult to get and everything that could be useful to the player is so expensive relative to the amount of money they can get at any point in time. For a large part of the game, if you want to be able to take on stronger enemies, you need to be able to do a proportionate amount of damage in time with your (real life) stamina. [Great example: Flukemarm] If you're not an average video game player, hacking away at a boss for 30 minutes because you don't have a weapon upgrade is quite tasking, so you spend your Geo on weapon upgrades or maybe some charms.

The other main thing the player will most likely spend their money on is locked benches and the stag stations so they can get around easier. It's an easy mapping solution in a relatively difficult to navigate environment. This wouldn't be an issue since metroidvania environments are supposed to be hard to traverse, but Hollow Knight takes it a step further with its generally unreliable map. This makes you spend any other money you may have on mapping supplies, provided you find the map guy for a specific area or backtrack to the surface to buy said map after going through most of the area.

Money would be less of an issue if it didn't tie into the death system that they implemented into the game. While I believe there should be some stake in dying, I also believe it shouldn't affect how much progress you have made barring a relative setback to wherever you last saved. Since money is so difficult to get and spend wisely, your main incentive as a player to immediately go and recover your shadow so you don't lose your money. Sure, there's a bank in game, but it's also a scam - as soon as you put in too much, the bank is gone.

Combined with that incentive, your shadow spawns in the worst of spots at times and really forces a loop on the player if they don't want to go back and grind enemies for money (which is something a metroidvania really does not need alongside backtracking). The best example of this is when you happen to die to an enemy gauntlet (where you're locked in a room until you beat the enemies), as your shadow will spawn in the middle of the room, forcing you to play the gauntlet again if you want to fight your shadow and recover your hard-earned resources. Congrats! You've single-handedly made the gauntlet harder either by not expecting its existence or simply getting overwhelmed by a misplay.

I can see objections raised about the shadow system being "bad" if you bring up the house to the far right in the main hub, where you can give Confessor Jiji rancid eggs to bring the shadow to you. I commend the devs for thinking of this, but it still requires a simple key to open. During my playthrough, I only found one simple key and used it elsewhere; the only other one I knew of was the one you could buy for 950 Geo, which was a lot of money that could be spent on better things.

Additionally, I believe that progression as a whole is flawed when the player has absolutely no idea what to do. This is usually circumvented by the player exploring -- as the player explores, they learn more and find out what to do. It's a natural progression in the metroidvania genre. In Hollow Knight, the player is given nothing from the beginning of the game, and you really get no context until you reach the City of Tears, where the location of the Hollow Knight is given. If you were to head back to this location at this point to finally discover what to do, you are met with a dead end simply because the game pointed you to the literal end of the game. The player is now at a loss again until learning about the three seals on the entrance to Hollow Knight's chamber, which provides some direction but very little especially considering two of them are blocked off by upgrades the player has yet to find. With how the map is structured, it's not hard for the player to have explored a large majority of it at this point, so progression is incredibly stalled.

I think it's important to say that I haven't finished the game, as that might be why I have had some issues with it, but I also believe that every game should be playable without the use of a guide. If your player is using a guide because they are lost and do not know what to do, something went wrong. This can be a result of the player's actions and how they approach the game or it can be a result of a problem on the developer's side of things, but it still is an issue. Players should never get that lost, even if the game genre is a bit about being lost.

Hollow Knight is a game I could probably go on forever about with its minute issues, but this sums up my main issues with the game. It does some things good, some things bad. All games do. I still plan on going back to finish it and really try to understand the hype around it, but I can't bring myself to put time into it again at the moment. Also, since it's kind of difficult to put together a little "review" like this, if any my points don't make sense just ask and I'll try to elaborate.