Designing Ys, Vol. 6: Yogleks & Omulgun

We arrive now on the doorstep of the endgame, at the worst boss of Ys I: Yogleks and Omulgun.

(Nobody knows which head is which, but I always assumed Yogleks was purple and Omulgun red.)

The idea behind the fight is fairly straightforward. Both heads float around the boss arena, bouncing off of the walls. Each head is surrounded by a ring of fireballs, one moving clockwise and the other moving counterclockwise, which slowly expand and contract as they orbit the bosses. In order to damage them, the player has to quickly dart between the fireballs as they get an opening, strike the head, and come out of the ring unscathed. To prevent the player from simply staying inside the ring, the heads magically swap positions every time Adol gets a hit in; only the red head is vulnerable to damage.

There are a number of issues with this fight. The first is that because the fireballs rotate in opposing directions, the head-swap means if the player doesn't correct their course immediately after making contact they'll run straight into the swapped head's fireballs as they try to exit the ring. The second is that it requires a level of pixel-perfect precision not found anywhere else in the game—Adol has to start charging while his sprite is still aligned with the lowest fireball of the two he's trying to squeeze between, and make minute adjustments to get out unscathed. The third problem is more an issue of the boss' comprehensive design: it gets easier as the fight goes on, rather than escalating in difficulty.

See, as Yogleks and Omulgun lose Hit Points, they also start to lose fireballs, one per every quarter of their maximum health taken off. Most video game boss fights escalate in challenge the further the player can make it, thus passing through one phase establishes they're ready for the next. With Yogleks and Omulgun, the player starts the fight able to handle the last phase, which results in a denouement when they finally get past the first two and the tension dissolves.

Most players take issue with Vagullion, but I would contend that Yogleks and Omulgun are the boss that really needed to be fine-tuned. They start out disproportionately difficult compared to the bosses before and after them, on a scale that one can't help feeling it was a mistake, and end up disappointing the player that actually sees their fight through to the end.

Of note is that Falcom's official user support query outright calls the boss impossible without the Flame Sword, which would otherwise be an optional weapon, and strongly recommends acquiring the Battle Armor and Battle Shield rather than relying on the Silver set. Their recommended strategy is to sit in the corner waiting for the red face to draw near before charging through it, as the middle of the room leaves the player too vulnerable to damage. As many players concluded back in the 90s, a riskier alternative is to charge the red one in the room's center as the two heads are converging and catch it a second time after the swap.

So we've just had two badly designed bosses in a row. It would have been entirely possible for Ys to have peaked at its fourth big battle and never fully recover. Thankfully, the final boss of Ys I is also one of the best bosses in any 2D video game.

Designing Ys, Vol. 3: Vagullion

The single most important weapon in Ys I is the Silver Sword. It is not the strongest weapon in the game; that's the Flame Sword, which it's 18 points weaker than. But the Silver Sword is the only weapon capable of harming the final boss, so unlike the Flame Sword it is indispensable to the player's progress. The credits will never roll without it.

Most games would give the second-strongest weapon in the game to the player in the final dungeon, or shortly before entering it. Ys gives it to them less than halfway into the game.

There are two immediate reasons the player needs to explore the Mines of Esteria. The first is to acquire the third Book of Ys, and the second is to acquire the Darm Key necessary to open the way to the final three books. In addition to these, the Mines are where the game's antagonist hid the Silver Armor required for the final boss, and where the player can find the Roda Seed. This last item is what enables them to speak with the massive Roda Trees on the overworld, which will eventually let the player dig up the Silver Sword from within their roots.

While the player can enter Darm Tower as soon as they have the third book and the corresponding key, doing so locks them off from ever returning to Esteria. To ensure that the player has all of the Silver equipment before proceeding, the last boss faced before entering Darm acts as an equipment check—in other words, it's supposed to be impossible to defeat without the Silver Sword, Silver Armor, and Silver Shield. And for some, it's just impossible to defeat in general.

Conceptually, Vagullion is similar to the Yellow Devil of Rockman fame. The boss begins as a single enemy, then splits into a swarm of bats that fly across the room to attack the player. Vagullion is only vulnerable in its unified form and only for a few frames, and like Nygtilger has a form of contact damage that will harm the player if they bump into its upper body. The pattern the player finds themselves pinned into is to hang close to the swarm, teasing it into attacking Adol, before darting away as it closes in and repeating this process until Vagullion reforms.

While simple in theory, there are several wrinkles to executing this strategy. First, while Vagullion is balanced around level 17, these are the player's naked stats at that level:

HP 85
ST 42
DF 35

And these are Vagullion's stats:

HP 150
ST 75
DF 56

For comparison, these are the player's stats with the fairly-average setup of Talwar, Small Shield, and Reflex Armor:

HP 85
STR 58
DF 45

Vagullion's numbers are dramatically inflated for the purposes of the equipment check, and even with the Silver equipment the bat's output is devastating:

HP 85
ST 74
DF 67

Vagullion goes from taking off a third of the player's Hit Points with each attack to shaving off 11%, but his swarm is also designed to get in two to three hits every time it makes contact, which provides the player with very little room to learn the boss' pattern before eating a Game Over. The player takes 12% off Vagullion with each hit and can bump that up to 24% with the right positioning, so they only need five clean hits to end the battle, but getting those hits in can be difficult because of one other property—Vagullion can feint the player.

The swarm is not required to reform unless the player is sufficiently far away. Thus the player that tries to simply pull away and loop right back, expecting the converging swarm to become a vulnerable Vagullion, gets a nasty surprise when it stops reuniting and instead begins chasing a player that's walking right into its trap. The probability of Vagullion feinting is determined by how far Adol is from the boss when it starts reforming, which director Iwamasa later recalled as being an addition to Vagullion's pattern created by Hasegawa Hiroshi, the second main programmer of Ys I & II. This behavior discourages the player from puppyguarding the boss, and introduces an element of randomness to its pattern that prevents it from being the exact same fight every time.

The combination of high stats, stringent equipment requirements, semi-random attack pattern, brief phases of vulnerability, and contact damage, all make Vagullion one of the most infamous bosses in Ys. It's not the most difficult boss found in the duology, but it is the one that claimed the most casualties in terms of unfinished playthroughs. It's difficult to say if the boss was supposed to be that hard—but at least when rebalancing the game for its "definitive" overseas release, Iwamasa did not see fit to make any adjustments other than the pattern changes Hasegawa came up with, whereas at least one later Ys I boss saw its stats modified and almost all major encounters of Ys II got an overhaul.