Just FYI! Your first attempt is not actually ten sentences! Those are sentence fragments at best. ;D
In your second attempt, your one-liner is a bit awkwardly phrased. Schools of grammar argue about whether a comma in a list preceding "and" is necessary, so I won't harp on that. It did look almost like a run-on sentence (or more specifically, a comma splice) at first glance, before I realized it was a list. You're also being extraneously verbose; if it's all that he can see, we don't really need to know the first thing that he noticed. I'd suggest rephrasing for a better flow. E.g.; "Upon waking, all that Axel could see was the multitude of contusions along his arms, shoulders, and chest."
Then- once again- you are repetitive with "To his observation" and "he noticed". You don't need to keep telling your readers the same thing twice in one sentence!
Next, you begin a sentence with "Few". Which few? The way your sentence is constructed indicates that you mean few contusions in general out of all the many contusions in the world, when you really mean "A few" in particular. :]
You use the phrase "implemented by fists". I think this may be a case of verb confusion, as it is a very odd way to say this. The word you were looking for was probably "inflicted".
"Unbeknownst to the man were the lacerations covering his thighs, calves and ankles, only having noticed the bout of excruciating pain when he had sat up." This is another awkwardly phrased sentence. It meanders as if you weren't sure where you were going when you wrote it. You might want to give an indication that these are different lacerations, perhaps by inserting "additional" before "lacerations" or the phrase "as well" after the list of lacerated body parts. You also give no indication of when exactly he sat up. You use "had" as if it were before the point at which you're narrating, but in the same sentence he was unaware of those lacerations!
That hyphen is not used correctly and should be removed. You don't particularly need any sort of punctuation there; it would be fine as simply "he came to the realization that this must have happened while he was under the influence".
"Did he get into a fight, an accident, who had witnessed this tragic event?" THIS is a run-on sentence/comma splice! You are smushing independent clauses together! "Who had witnessed this tragic event?" should be its own sentence, or at least be properly separated with correct punctuation such as a semicolon.
(I'm also not sure if you are using italics for emphasis or for indication of the character's inner dialogue. If so, does he think in third person?)
"Most importantly, he wanted to know how all of this had occured in the first place." You misspelled "occurred"! This also feels a little wordy. I'd suggest rephrasing.
In fact, a lot of these sentences feel a bit stiff and wordy! When you write a paragraph, you should read it over and question what you've written. Is this word or phrase necessary to your sentence? Are you using this word instead of a more common one because it paints a better picture, or because you were trying to avoid the common term? Does this sentence roll off the tongue, or do you stumble? Does this paragraph stick to one cohesive point or should it be broken down into two paragraphs? Are you using enough adjectives for descriptive effect?
Well, you get the idea! I hope that helped. :]