Rating: Middle of the Road so Would Not Keep Reading.
The Good:
It's generally humerous.
You caught my attention at times with some of the potential routes it could take. At the point where they're saying he could turn into a woman I thought: "You don't see that a lot in web novels, you think that'd be popular."
Honestly You've Only Got One Real Problem
It could be punched up in many ways, but if you're looking for things that could outright use improvement: the length. More specifically the amount of words you use to establish a point. You could chop two pages off of the seven you've written here and not lose anything. Everything feels elongated and meandering.
Excercise time. Here's your first page. Let's look at what we need and what we don't.
"It's bright. My eyes shut reflexively, unable to endure the searing glare. I'm absolutely exhausted, like I've just ran a marathon after scaling a mountain I had to reach by swimming across the Atlantic. My head's spinning and I've got a strong urge to vomit, which isn't helped by the nauseating smell of ozone that permeates the air all around me. Good descriptive start.
"By Sunder—sire, look!" I make out a wizened sounding voice through the fog in my brain. So I'm highlighting what can be cut in red. What does this add? If we start with the final line about the "Summoning veil", then you lose nothing because all this sentence does it establish that there is a speaker.
He's answered by a stern rumble, and it takes me a second to realize that's someone's voice and not the sound of the earth quaking. "...Complications in the..." Is about all I can catch in my beleaguered state. You establish that 1) The voice is a person and not an earthquake which the reade knows and 2) The MC is tired which we know. Cut this without exception, it offers nothing.
A heated discussion breaks out between them judging from the rhythm of their voices, but I'm too tired and out of sorts to care enough to pay any attention to it. Eventually there's a lull in the conversation, and just when I'm about to drift off to blissful slumber a powerful surge of energy courses through my body. I bolt upright on staggered feet, shielding my eyes from the world of light that surrounds me. First half gets us nothing. There is no foundation to understand the argument so it means nothign to us. The second half I've highlighted in orange because there is a kernel of something workable here if you rephrase or incorporate it elsewhere. It establishes that communication is unclear and they fix it. We'll just say orange means weak.
"W-who's there!?" My voice comes out rough and ragged as I stumble about blind. "Where am I?!" We know he's out of sorts, but it's also normal for him to voice his confusion. There are better ways to convey this. It would normally be orange, but see my next note for why I'm marking it delete
"Ah! Please, stay where you are!" The aged voice responds, his tone petulant. "You're liable to injure yourself if you move out too far!"
"Don't tell me what I can—AARGH!!" My arm brushes up against something scalding hot and I jump back screaming. "WHAT IS THIS!?" Like here. He is establishing that he doesn't know what is going on and voices it in a way that is active. It's also redundant. If you delete the above, this just works.
"You're currently being contained by the summoning veil," the same voice hastily explains, "it's merely a temporary measure for your protection!"
As a counterpoint: I'll include what my version looks like. Ask yourself, is there anything in this version that is lost.
It's bright. My eyes shut reflexively, unable to endure the searing glare. I'm absolutely exhausted, like I've just ran a marathon after scaling a mountain I had to reach by swimming across the Atlantic. My head's spinning and I've got a strong urge to vomit, which isn't helped by the nauseating smell of ozone that permeates the air all around me.
"You're currently being contaied by the summoning veil," the same voice hastily explains. "It's merely a temporary masure your protection."
I hear the voice but I can only make out vague, scratchy shapes in my vision. I try to speak but the sound is garbled.
"Complications in the-" It's a second new voice, but the sound is cutting out.
A powerful surge of energy courses through my body. I bolt upright on staggered feet, shielding my eyes from the world of light that surrounds me
My vision is clear now, but I have to crane my neck up to meet his gaze. The man's huge—easily close to seven feet tall if not taller—and has a build to match. The elaborate surcoat and mantle he's wearing seem almost unable to contain him all. In contrast, the expression on his rugged face is gentle, almost remorseful. A hint of a smile tugs on his lips as he speaks to me that doesn't quite reach his somber blue eyes. The man's sheer presence is so overwhelming that it actually takes me a moment to think of what I want to say to him. I moved a later paragraph here because it's weird for them to be conversing without visuals described.
"Ah! Please, stay where you are!" The aged voice responds, his tone petulant. "You're liable to injure yourself if you move out too far!"
"Don't tell me what I can—AARGH!!" My arm brushes up against something scalding hot and I jump back screaming. "WHAT IS THIS!?"
"Ulgen, for goodness sake, lower the opacity!" The deep voice orders, clearly irritated. There's a sound like steam whistling from a kettle and soon the blinding light begins to dim, revealing two dark figures standing in an unfamiliar chamber not unlike some medieval castle keep. The larger of the two approaches, his regal bearing evident as he steps closer into the light. "Hello. I... don't suppose you recognize me?" Once again, moved this from before. Makes way more sense directly juxtaposed to the above.
"Oh, obviously!" I snarl as I nurse my burnt elbow. "Who the hell are you and what the hell is a 'summoning veil'!?" And on we go, organizing things a bit more logically.
Let's compare with me ignoring the parts I pulled from later:
Your version that I initially quoted was 276 words- about 1 page.
My version of your words (with one addition) was 193.
As a ratio, you lost 30% just on the editing which is a big problem. Imagine that for every two pages you read, the third page is something you've already read, but you're forced to read it. Inefficiency in story telling is the single most important factor for creating active readres and creating enjoyment at this level of writing.
OVERALL
Just see the above.
You can butter me up all you like but you'll never fit me in a toaster.
Rating: Would not keep reading.
I guess I'm in an editing mood, let's just do that:
1) Your first two paragraphs are a nightmare.
Tears blurred my vision when I first woke in my bedroom early morning that felt strangely out of place. This is modifying morning, that's what it's next to. It's apparently modifying bedroom. Also, he just woke up, the default interpretation from the reader is that it's morning so just cut it, dont' even bother rewriting. Whatever I was dreaming about last night had been a horrible nightmare, enough to leave me a sloppy mess. Still, it was nothing compared to where I h⁸ad woken up. You already devoted a sentence to saying he woke up in his bedroom. This adds nothing.
This room used to be my bedroom ten years ago before the Era of Dungeon Break began. So you start talking about the bedroom, then it transitions to the dream, now with this paragraph, you're back to talking about the bedroom. We've lost all logical flow. Either I’m still dreaming, or I’ve died and gone to heaven about to see my little brother and mother again, who didn’t make it on that day.
Your first two paragraphs should look like this (or some equivilancy):
Whatever I was dreaming about last night had been a horrible nightmare, enough to leave me a sloppy mess. Still, it was nothing compared to where I h⁸ad woken up. This room used to be my bedroom ten years ago before the Era of Dungeon Break began. Either I’m still dreaming, or I’ve died and gone to heaven about to see my little brother and mother again, who didn’t make it on that day.
Even reduced down to the active words, it's not a killer opening.
2) My jaw dropped to my chest and my hands started to tremble upon the realization that last night’s dream was no dream. Weird juxtaposition again. You break up the paragraph about dreams with an RPG text box. This appears to be about that until it loops back around making it feel non-sequitor.
3) Wait. What about Mom?
I finally let Benjamin go and asked him, “Mom. Where is Mom?”
And so on. There are a lot of little places we could pick apart, but mostly this was just a reaction to the first two paragraphs which read so bizarre.
OVERALL:
I actually think the first half is very good. There's this strong insistance on emotion and I'll even say I don't think I've seen this set up before where loved ones come back as a side effect of the LitRPG. Cool and the writing and tone are appropriate. I'd give that a thumbs up outside of some of the writing needing polish.
The second half is rough though. You move away from the narrative format to just exposit information and that's no fun. Most of this information could be relayed actively, fed to the reader by what's going on. Like the mother/ brother are mad and he says, "No you died. There were these portals, and then. . . .
It's so much information that I wouldn't even try to put it all in one chapter. Find organic ways to spread that out.