Blloodsword series is great for its story and for its game mechanics.
In this first instalment of the series, you have a very good induction in the amazing game mechanics: you can play this game with one to four people (very novel for gamebooks!) and the complex fighting ruleset, including magic, ranged combat, melee combat, movement on tactical maps, etc. is a small gem for connoisseurs!
However, the story of this first book of Bloodsword series is particularly weak and uninspiring: it's fundamentally a dungeon crawl in a hell-like dungeon, with lava lakes and horrible monsters that need to be hacked and slashed until you get to the end and win the challenge. Nothing to do with the great background stories of books 2 and 3 above all!
This book is therefore a good presentation and ruleset induction, waiting for "the really good ones". If this gamebook was published on his own, nobody would remember it nowadays, while Bloodsword is now considered by the expertes one of the best gamebooks series ever.