1: Game stability, general changes. (TL:DR - Bugs repaired, things implemented, keep up the good work.)
2: Items (TL;DR - Rares could be tweaked, recipies start to drop too late, staves are obsolete. Apart from that: Itemization is almost perfect.)As far as my experiance goes: perfect. Game didn't crashed a single time for me on whatever occason. FPS change is solid, and the sprite animations don't glitch due to it. One second delay on skipping intro and logos is irritating, but nothing more. Definitely not a priority. Some people are having mouse-lag issues, but as I stated in another topic: It can be their OS problem, not the game itself. Need some tests with build-in Windows "enchance pointer precision" option, MarC mouse fix and v-synch. I've heard Belzebub's has sound problems on WINE, but they can be somehow fixed by forcing the usage of specific drivers in some way or another. The game also seems to have no problem with dual GPU's of laptops, which I was worried about. Good work.
While I feel waypoints were not entirely necessarily, I like that I don't have to run to the Cave/Catacombs entrance every time. I've noticed quite the number of bugs you fixed, especially the wretched chain lightning missing tiles and projectile not hitting targets. Kudos for that especially.
Item Sets: Found (or provided by other charactar) on appropriate level give huge advantage, especially on lower difficulty. While single set items are generally less usefull that a good craft/rare, the effectiveness of two or more items are sky rocketing. It was also a good idea do limit most sets to 3-4 items at best. Not only does this allow the rest of character's gear to compliment, but also actually allows players to complete sets. All in all: I think Belzebub is the second game/mod in which Item sets are done RIGHT, first one being MedianXL.
Unique Items: Solid. New or recovered uniques are awesome, usefull, and they carry on the legacy of D1: They have bad sides as well as good sides. I also like the way old uniques were tweaked a bit (namely thinking cap not having one durability). The idea of introducing "alternate" version of certain unique items is also interesting (The Undead Crown / Helm of Spirits, Tarnhelm / Thinking cap).
Rare items: Potentially the best items one can carry. Fishing for Rare items in Gheed's item pool is suprisingly good money sink, as I personally drowned A LOT of gold already, and got few items that are insanely good on various character classes. One thing is: They seem to be unable to roll negative values. I personally think that allowing them to roll one negative stat would add some flavour.
Magic items: Those on the other hand suffer from a bit too much negative values, and the effect of this has big impact in the start of the game. It helps control the amount of gold, and well as crafting materials, but it is a bit of a overkill.
Crafted items / Crafting system: First thing is I do not understand the reason of high prices for selling recipies. Not that it matters much, but selling a single recipe for 35k+ gold is insane. Second thing is the difference between player level and recipies level. Once the players starts to find his first recipies for crafted items: they are already rendered obsolete by items directly found by the player. An easy fix to this is allowing the recipies to drop earlier. "second tier" recipies also suffer a bit from this problem, but they are still good. About the crafted items themselves: Provided the player has luck for rolls and patience for farming: They are the best items player can get. I also fail to see reasoning behind not being able to put crafting mats into trade stash.
Staves problem:
Sheer amount of stat and bonuses from shield and weapon usually renders two-handers useless. This is especially visible with Sorcerer and his staves, as without INSANELY good roll on staff (and only rare and craft that is) it's suicide to not use weapon&shield. Perhaps building-in permament bonus spell power in all staves would fix the problem.
Relevancy of properties:
I like the way many classes are suppose to use many different bonuses from weapons instead of going only, for example - Magic/Mana/Spell lvl. Faster Hit Recovery, Bonus Crit, Bonus Crit damage, Faster casting, Magic Find: It all suplements characters instead of being useless addon to single, most valuable stat.