Story & World
None of the Deep Dungeons have a particularly gripping storyline but the title alone gives a good indicator that one will be immersed in much crawling of the dungeon variety. DDIV manages to fare a little better than its parents by fleshing out the non-Shen characters and having more solid side quests. The main quest of hunting down the black sorceror, though, gets somewhat lost during the midgame as the party has to deal with the various problems that the villagers have, none of which have anything to do with getting the revenge. There was no Ruu this time but I can't decide whether that is a good or a bad thing so I'm just going to be neutral about it.
Despite its title, DDIV has no dungeons to speak of, just caves, castles, forest, and mountains. Of course, in the game world, these all function just like a dungeon but with a wider variety of skins. After how samey the first three games looked, this was a great decision on the part of the developers. The only better decision would have been not to make a Deep Dungeon IV in the first place (ooh! sick burn). The open-endedness of any game world is always appreciated, even if here it caused me major problems at certain points (totally my fault, though). With lots of villages (and villagers) and more distinctive areas, DDIV comes out ahead of its predecessors in having a more worldly feel. 8/20
Only three characters are available here, down from four in DDIII. There is a fourth slot available for temporary characters (escort quests) and it can also be filled during combat with one of the two summoning spells. The cost of having better developed secondary characters is that there is no room for any kind of party class configuration. Switching out Caleph for Saito hardly counts as they are essentially the same character. Development is further reduced by never giving out any stat-boosting sandwiches other than in the first forest.
The standard model for magic is used here and thankfully all the characters have access to a decent amount of spells. While each character definitely had an area that they were more focused in, their entire spell list wasn't stereotypical of their role. Items that replenished HP or MP are painfully underpowered and become a waste of an item slot very quickly into the game. While annoying, this did add to the challenge but perhaps Erick and Caleph/Saito could have been a little more robust in regular melee to compensate. 5/20
Combat & Monsters
Another regression from DDIII, combat is back to the typical scheme of mostly mashing a button to assign melee attacks. The situation gets a little better later in the game when the characters have more MP and spells to play with. A big plus in combative magic is that status ailment spells usually work on enemies! Nothing makes a big batch of nasty efreets seem like piddly newts after being completely silenced and/or slept (at least until it wears off). Monsters had more special attacks than in the previous games (not a difficult feat), which helped make battles a little more interesting. 5/20
Graphics & Sound
The "dungeon" tiles are automatically going to score better due to them having vastly different looks to them but I will say that, even on their own, they look quite nice. Enemies are well drawn with not an unreasonable amount of palette swapping. Due to the layout of the screen, larger creatures appear to be squished a bit and I'm sure the graphic designer had fun trying not to make them look too ridiculous.
Music has improved and almost — almost — makes it to mediocre status. Sound effects are practically nonexistent, just a few beeps when navigating menus or casting a spell. 8/20
No manual mapping! No manual mapping! Huzzah! This one aspect made DDIV much more tolerable than the previous titles. The saddest part is that, even if I did have to make maps, it wouldn't have been that bad as areas are compact and laid out in the traditional setup of corridors and rooms. It's only by having the Deep Dungeon moniker attached to the game that makes this stand out from what is otherwise quite a normal map structure.
The economy is strong with this one. I only ground on chests right at the beginning and relied on natural exploration for the rest of the gold. After blowing most of my cash on the two flutes, shit started getting real as resurrecting characters (I'm looking at you, Caleph) got increasingly more expensive as levels were gained. I was down to my last few farthings, I was, before fortunately beating Cymer. The only downside to the economy is that there wasn't much to purchase by midgame other than consumables (most of which sucked).
The pacing was good and the rough patches I encountered were utterly of my own doing. I do consider it a plus even to be able to hit such patches as long as it's because of my own decisions. DDIV took about half the time of DDIII and was closer in length to the first two games. It's a little sad when one of the best things about a game is how short it is but, for the Deep Dungeon series (excluding DDIII), this is one of its biggest merits (but it's still not getting points for it). 12/20
Final Ranking: 38/100