Unfindable word 爆絶級 in Japanese Mario Maker level name

Question

I just watched a video where Thomandy (a youtuber who plays games) plays two Mario Maker levels, and one of them is called:

My transcription of this level by Daiki is:

挑戦者現れろ！！！　　爆絶級

Assuming I didn't miscopy, the first part should be:

挑戦者現れろ！！！ | Chousensha arawarero!!! | Let the challengers appear!!!

The second part is my problem. The last character should be -kyū, meaning "class", but the rest seem to form a word which is nowhere to be found in my references, and indeed Google won't transliterate it. From JEDict, my guess would be:

爆絶級 | bakuzetsu-kyū | bomb-sever class

However, besides being uncertain about transliteration (just look at how many readings the Wiktionary lists for the first character!), this translation makes little to no sense to me. So:

What does 爆絶級 mean? And how do I read it?

Answer 1

「爆絶級」 seems to be a coined word to express a degree of difficulty. It is fairly likely to read 「[爆]{ばく}[絶]{ぜつ}[級]{きゅう}」, which is obtained by simply concatenating on-yomis.

Firstly, 「級」 is for "class," as you guessed.

Secondly, 「爆」 is for explosion rather than bomb, in my opinion. Explosion is employed to express its fierceness. Though there is no strict rules, 「爆」 impresses us as the level is fairly high.

Lastly, 「絶」 is likely to come from the word 「[超絶]{ちょうぜつ}」 ("transcendence"). If 「超絶」 is used for expressing difficulty, it would be "absolutely high." The kanji 「絶」 itself has a nuance of "absolutely" or "definitely" (as in 「絶対」), "separate" (as in 「隔絶」) or "the highest" (as in 「絶景」) The basic idea of 「超」 is "super" and it has the nuance of "great" or "very high," so 「超絶」 is a combination of two kanjis both expressing "very high."

Here 「爆絶」 is created by replacing 「超」 with 「爆」. I'm not sure (and there's no answer) which of 「超絶」 and 「爆絶」 is higher, but both should be really high.

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Edit: as for the reading of 「[爆]{ばく}[絶]{ぜつ}[級]{きゅう}」, on-yomis other than 「ばく」 for 「爆」 are really rare (indeed, I can't recall them). In Wiktionary, all of them are marked "non-Jōyō reading" or "historical." The same applies to 「絶」 and 「級」. 「ぜつ」 and 「きゅう」 respectively are only on-yomis commonly used.