The transparent squares were set to some ad hoc values, it wasn't something I'd adjusted properly (and thus why they look jarring).
In any case, I think I've found a better solution to how the view space is put together. Essentially it's going to be composed of 6 'slices' 3 rows of 2, and then a background image (which will shift and change depending on your position on the map and the direction you are facing). I am going to manually scale down the slices (thus creating 3 images per slice) and extend middle and background slices so that they reach the edge of the view space and also so that I can create their fading by hand (so that it meshes more natUrually with the background).

After reading around on the net I decided to bump up the minimum resolution to 1024x768 but I am going to support resolutions beyond that, up to 1080p (which is what I use), and thus offering more HUD space for more direct access to character info, etc.
I've been working on the battle system as well, the game is going to be somewhat
card-based. Each time you enter a dungeon you put together a deck of abilities (or use a pre-made one). These are things like spells, special attacks, etc. but also cards that can be used to change certain things about the dungeon. Once you use an ability it is removed from the deck (but not from your collection) so you have to be careful about what abilities you are using where because you could wind up leaving yourself empty-handed for a critical fight. The cards are not randomly dealt to you in battle, though, you can choose any card the character can "play" from your current dungeon deck.
The ability cards have a specific "type" (sword skill, arcane magic, prayer, trickery, etc.) and each character has restrictions on what types they can use, so you want to build your dungeon decks around the characters in your party. In addition to ability cards each kind of equipment and item is also a card, and a character can carry up to 8 equipment/item cards (any combination of weapons, armors, items, etc.) All equipment and item cards have a durability value and if it is reduced to 0 the card is destroyed (though weapons and armor can be repaired, raising their durability, if they haven't already been reduced to 0).
Weapons use up 1 durability per attack (some will special abilities that can be used in lieu of a normal attack but cost more durability to use). Armor uses up 1 durability every time you take damage. Items use up 1 durability every time they are used (with things like potions, etc. usually having only 1-3 durability points to begin with). Relics will not have durability and function in a supplementary manner (for example, a Heart Pendant giving +10 HP while in your character's inventory). You can carry multiple weapon or armor cards (and thus alternate between any you carry during battle) so a big part of the strategy is planning the right combo of weapons, armor, items, and relics.
There will be
no level gaining or required grinding in this game. Armor functions a lot like it does in
Final Fantasy Tactics where the armor you equip determines your HP, this is the primary means (relics aside) of upgrading your HP. Weapons are the primary means of upgrading your damage. Etc. What this means is your "level progression" is your card collections. The better the cards you find the stronger you can make your character. It also means that at almost any point you can completely customize your party and form new strategies, you are not shoehorned into specific builds.
Each time you defeat a group of enemies you have a chance recieve X number of cards (at a minimum of 1). So rather than just gaining XP, every battle is like a mini-lottery where you might win big. There will also be a
Persona-esque mid-battle mini game where you can try to acquire a summon card from an enemy (which let's you summon that kind of creature during battle as the 5th character in your row).
Also of note, the game has a day and night cycle and time passes with each "step", or room transition, you make in the dungeon. Some events, enemy groups, abilities, etc. will function or be completely different depending on whether it is day or night (or in some cases evening or dawn). There are
no random battles in the game, you can see the monster groups (well, in abstract form) before you encounter them and they move about the dungeon like the
FOEs do in
Etrian Odyssey. Once they are defeated they are taken off the dungeon map, but at each cycle change (day to night, night to day) the dungeon gets repopulated (so there is a certain sense of urgency in some cases).
I am working on a prototype of the battle setup and once I got something playable I will post it for feedback.
EDIT: I forgot to mention there are also Loot cards which are things like gems, metals and other repair material, animal parts like wolf fur, herbs, food, etc. which can be used to repair equipment, create potions, persuade (in the Persona-esque battle mini game), and so on (if you have the appropriate skills). Any loot card that is not used during dungeon exploration is "cashed in" automatically when you exit the dungeon and you are awarded money equal to the total value of all your cahsed in loot. While "in town" you can buy (and sell) equipment cards, buy ability cards, change your party roster, and so on.
Ironically I had Arcana in mind when I started the project, it is one of my favorites dungeon crawlers.
Judging from your interface layout, the player will wander the dungeon alone right?
No, you'll have a party consisting of a character you create at the start of the game, 3 characters you convince to join you, and 1 monster/creature/character you summon in battle.