YMMV / Death's Door

• Awesome Bosses: All of them, really. The bosses are tough (but fair), demand concentration and playing well, and prevailing over them just feels awesome.
• Awesome Video Game Level: The Inner Furnace has plenty of setpieces (such as dodging bombs on a conveyor belt while also avoiding pistons), but what makes it unforgettable is the music, a tense string piece that uses the background machinery noise as percussion.
• Continuity Lockout: The secret ending is one big callback to Titan Souls, the developers' previous game, and will mean little to players who didn't play it. Truth is revealed to have been the reason the Free Crows manipulated and aided the player character, but he didn't actually have anything to do with the Lord of Doors's actions and the Crows had plenty of reasons to help end the status quo regardless, so to new players this can come across as a meaningless background detail.
• That One Boss: Or "mini-boss type" in this case. You'd be hard pressed to find someone who actually likes fighting the mace knights that guard certain areas. Compared to every other enemy and boss in the game, their attacks are barely telegraphed. Even worse, their maces have very long and wide hit boxes and track the player, meaning that pre-emptively dodging only guarantees getting hit. Couple that with inconsistent vulnerability windows and a fairly large health pool, and you get a frustrating encounter.
• That One Sidequest: Collecting and planting all the seeds is actually necessary to unlock the secret ending. Thankfully the game does highlight areas that still have items to discover, and in the post-game The Rusty Garden Trowel and Pothead further help to narrow down locations of seeds and pots respectively, but players who only used seeds sparingly are in for hours of additional grunt work.