Surprisingly decent for such an old level, but Steve didn't go deep enough with the concept.

Loobinex perfectly summarized the level. I'll add that Steve might have severely underestimated how strong an Avatar is as the big boy can pretty much solo everything except for the very final wave unless you train him to lvl 10. You could replace him with a Knight and it'd be more fair. Most of the enemies are low level creatures and except for maybe the Hornies, none can challenge an Avatar. Especially a lvl 5+ one thanks to the level up specials.

3/5 since it's such an old level 1/5 difficulty, the only threat is the final wave but you can ignore it. Even then, it's manageable thanks to the Avatar.

Now this one is interesting, but it needs some polish. You don't have to build a dungeon, don't have a portal and start with a bunch of heroes (including a tunneler and a lvl1 avatar) and no create-imp spell. It almost looks like you need to finish this level in first person and leveling up the avatar, but you'd be much better off claiming stuff with your tunneler (and the single imp you find) and collect the dungeon specials on the map. Keeping your only two workers alive is most of the challenge and I actually used up all my resurrection specials to get them back. There's also a reveal map special you are expected to find and it helps a ton, but it also highlights the flaw,... you can now dig in complete safety, and use your destroy-walls spell to cheat your way through the large hero fortress that makes up the northern part of this map. You have all spells(except create imp) and start with a million gold so you could exploit this in many other ways as well. If you have the patience you could win by only casting lightning. I decided to go round back and take a prison, torture room and training room instead. I then lost my imp for the last time, and hated my tunneler so instead of training my units I decided to use my destroy walls spell to reach the heart room without fighting instead. When I got there a massive army appeared that would have killed me if I would not have destroyed to heart to win the game instead. Despite the flaws, still worth playing.