Nemesis (Arcade)

Nemesis
Also known as: Gradius (JP) Developer: Konami Publisher: Konami Platform: Arcade (Konami Bubble System (JP original), Konami Nemesis/Konami GX400 (JP conversion and INT)) Released in JP: May 29, 1985 Released in US: December 1985 Released in EU: September 1985 This game has unused enemies. This game has unused graphics. This game has unused music. This game has regional differences. This game has revisional differences.

Nemesis is Konami's 1985 arcade game that's better known by pretty much everyone at this point as Gradius, its original Japanese name. Your precious Konami Code can't save you now!

Unused Graphics

This square-shaped robot has what looks like a diamond-shaped pinball flipper. Seems like it could shoot out bullets, maybe? Sounds about right.

Another unused enemy design that kind of looks like a pinball bumper.

Unused Music

ID	Track	Notes
46		This track isn't actually in the sound test, but it's still in the ROM. It's a happy little tune that doesn't really fit the game's atmosphere too much. This was reused much later in Gradius ReBirth as the ranking screen music.
47		This nondescript jingle is #23 in the sound test.

Regional Differences

	Test Mode Changes	Morning Music Countdown and Game Title Transition Speed	Title Screen	Starting Lives	Support Name	Continue	Game Flow	Difficulty
gradiusb	None	Original	No background	Original	Option	No	Original	Original
gradius	None	Altered	No background	Original	Option	No	Original	Original
nemesis	Some	None	Background	Original	Multiple	Yes	Altered	Altered
nemesisuk	All	None	Background	Altered	Multiple	No	Altered	Original

• gradiusb is the original Japanese version. It runs on the Konami Bubble System hardware. This is known internally as Version A.
• gradius is the Japanese version converted from the Bubble System to a standard on-board ROM (exactly the Konami Nemesis/Konami GX400 Hardware) due to the commercial failure of the Bubble System for being more expensive than ROM boards and extremely sensitive to electromagnetic fields. Despite being an hardware conversion, waiting times have only been reduced and like gradiusb this is known internally as Version A.
• nemesisuk is the European version of the game and assumed (by MAME, anyway) as "World". Unlike gradius, the game is not a conversion of the original Bubble System version. But a version of the game rebuilt from scratch directly on the Konami Nemesis/GX400 hardware. Because of this waiting times are removed and the Morning Music sequence was removed and replaced with a generic RAM/ROM check. This version plays like gradiusb/gradius, buy it has some gameplay and aesthetic changes, later reused in nemesis. This is known internally as Version E.
• nemesis is the North American version of the game. Based entirely on nemesisuk, this version has a number of coding changes, some of which it shares with nemesisuk and and an harder difficulty. This is known internally as Version D.

Test Mode Changes

Gradius	Nemesis

Text in the test mode screens uses palette 0A in Gradius and palette 00 in Nemesis. It's not clear if this is a bug or some kind of attempt to make the text more readable. If it's the latter, they missed the Demo Sound and Coin A / B dip switch variables.

nemesis	nemesisuk

In the nemesisuk set, the text "EVERY BONUS", used for subsequent bonus lives, was rewritten to the more accurate "AND THEN EVERY".

Morning Music Sequence and Game Title Appearance

Gradius (Bubble System)	Gradius (ROM Version)

Gradius is famous for its Morning Music sequence, present only in the Japanese versions. In the original gradiusb set, the game's bootup estimated time is about one minute. During the warm-up countdown the Konami's "Morning Music" song is played. The game's title appears with a striped effect. In the gradius set, the game's bootup estimated time has been reduced from one minute to 30 seconds, understandable from the warm-up countdown which goes down faster than it should be. This also means that the "Morning Music" can't play out in full. The game appears with the same striped effect but in hyper speed. This is because of the game's Bubble System conversion to the Nemesis/GX400 hardware.

Title Screen

Gradius	Nemesis

In addition to the obvious title change from Gradius to Nemesis, the title screen in the overseas version features a background as opposed to a black void, based on the artwork seen on the game's arcade flyer.

Game Demo

	Each version of the game has a different demo. In gradiusb and gradius, the demo player starts out with three options and never uses the Speed-Up power, which is maybe not the best way to show off how the game works. Still, it's the only one of these three demos that demonstrates the Double power-up. The demo ends at the start of the volcano section.
	In the nemesis demo, the demo player uses every power-up but Double and Shield. This is also the first demo to show what the blue crash capsule does, and how the Option pods can let the player take shelter while shooting. The demo ends with the demo player destroying the Big Core and the Vic Viper. Surely, a tragic ending.
	The nemesisuk demo is basically the same as the nemesis demo but with more skilled play. The demo player also gets three Option pods compared to nemesis' two. The demo ends with the demo player dying to Big Core's first shot.

Starting Lives

Players start with 3/4/5/7 lives in gradiusb, gradius and nemesis, depending on the how the "Lives" dip switches are set. In nemesisuk, this was changed to 2/3/5/7 lives.

Continue

The US nemesis set is the only version that allows you to continue after getting a game over. In gradiusb, gradius and nemesisuk, if you lose all your lives, you will get a game over and will have to restart the game from scratch. nemesis also has a limit of up to three continues, so losing all of your lives after continuing three times results in the same gradiusb, gradius and nemesisuk treatment.

Note that in nemesisuk, the text for the continue screen is still in the ROM, but unused.

Support Name

Gradius	Nemesis

The orange orbs that follow and fire with the ship are called Options in Gradius and Multiples in Nemesis.

Game Flow Changes

Changes that make the boss fight portion of each stage take less time.

• The volcanic eruption at the end of stage 1 lasts 1024 frames in Gradius, but just 512 frames in Nemesis.

In Gradius, the volcanoes will first erupt slowly, then speed up every 128 frames. Max speed is reached at 512 frames.

In Nemesis, they will erupt just once at the slowest speed before suddenly switching to the fastest speed.

• The enemy rushes in stages 3 and 4 last 1004 frames in Gradius and 768 frames in Nemesis.
• At the end of stage 5, it takes 1016 frames for the boss to show up in Gradius. This wait was completely removed from Nemesis.
• At the end of stage 6, the boss barrier will self-destruct after 260 frames in Gradius. This is just 10 frames in Nemesis.
• The final boss self-destructs in 688 frames in Gradius and 656 frames in Nemesis.

Difficulty Changes

The actual game difficulty is calculated through the following formula: (TimerVar + LevelNum + BonusVar + OptionsNum + DipVar) / 2. This value is capped at 15.

• TimerVar is the amount of time elapsed since the last death. In the original sets, this increments every 1000 frames. In nemesis, it will increment every 768/608/512/384 frames, depending on the value of the difficulty dip switches.
• LevelNum is how many levels you have completed. In the original sets, this value is multiplied by 3 for calculation's sake, while nemesis just uses the raw value.
• BonusVar adds difficulty based on the power-ups you collected. Like the TimerVar, these values are static in the original sets and vary with the difficulty dip switches in nemesis:

• If you have the Missile upgrade, add 2 in the original sets and 1/2/2/3 in nemesis.
• If you have four Options, add 2 in the original sets and 1/2/2/3 in nemesis.
• If you have the Laser upgrade, add 4 in the original sets and 3/3/3/4 in nemesis.
• If you have the Shield upgrade, add 4 in the original sets and 4/7/8/10 in nemesis.

• OptionsNum is the number of Option ships you have, multiplied by 2 in the original sets and by 2/3/4/5 in nemesis.
• DipVar is the numerical value of the difficulty dip switches.

• In the original sets, Easy is 0, Normal is 2, Hard is 4, and Very Hard is 6.
• In the nemesis set, Easy is 0, Normal is 4, Hard is 8, and Very Hard is 10.

Both TimerVar, BonusVar, and OptionsNum are set to 0 at the start of each game loop.

Fan bullet speeds
Note that there are four different Fan subtypes: One that never attacks, one that only attacks if the difficulty is greater than 7, one that only attacks if it's greater than 11, and one that always attacks. They all use the same bullet speed table, they just have different jumping-on points.

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	1.000	1.000	1.000	1.125	1.250	1.375	1.375	1.375	1.625	1.375	1.500	1.750	2.250	1.625	2.375	2.375
Altered	1.000	1.000	1.000	1.125	1.375	1.500	1.750	2.000	2.250	2.250	2.500	2.500	2.750	3.000	3.000	3.375

Dee-01 bullet speeds and firing delay
If difficulty > 7, Dee-01 will fire 2 shots in a row; If difficulty > 11, Dee-01 will fire 3 shots. The delays listed here apply after the last shot is fired.

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	1.125 112 frames	1.125 104 frames	1.125 96 frames	1.250 88 frames	1.375 88 frames	1.500 84 frames	1.500 84 frames	1.500 80 frames	1.750 72 frames	1.625 84 frames	1.750 72 frames	1.625 80 frames	2.250 64 frames	2.125 64 frames	1.750 64 frames	2.375 64 frames
Altered	1.125 104 frames	1.125 96 frames	1.125 88 frames	1.250 88 frames	1.500 64 frames	1.500 56 frames	1.500 48 frames	1.750 40 frames	1.750 40 frames	2.000 32 frames	2.000 32 frames	2.000 24 frames	2.000 20 frames	2.000 20 frames	2.250 16 frames	2.250 12 frames

Jumper bullet-spread counts

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	3	3	3	3	4	4	4	4	4	3	4	4	4	9	9	9
Altered	3	3	3	3	4	4	4	4	4	3	4	4	4	4	4	9

Hatch-type enemy spawn counts

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	3	3	4	3	5	6	7	7	8	8	10	7	10	7	10	10
Altered	3	3	4	6	7	6	7	8	9	8	10	9	10	9	10	10

Beans bullet speeds

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	1.125	1.125	1.125	1.250	1.250	1.250	1.375	1.750	1.375	1.625	1.375	1.875	1.625	2.125	2.125	2.375
Altered	1.125	1.125	1.125	1.250	1.250	1.125	1.125	1.125	1.125	1.250	1.250	1.250	1.500	1.750	2.000	2.000

Mother fire delays & spawn counts

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	64 frames 2x Child	60 frames 2x Child	58 frames 2x Child	56 frames 3x Child	56 frames 3x Child	52 frames 3x Child	56 frames 4x Child	48 frames 4x Child	40 frames 4x Child	44 frames 4x Child	48 frames 5x Child	44 frames 5x Child	56 frames 6x Child	48 frames 6x Child	36 frames 7x Child	32 frames 8x Child
Altered	64 frames 4x Child	60 frames 4x Child	58 frames 4x Child	56 frames 5x Child	52 frames 5x Child	52 frames 5x Child	48 frames 6x Child	48 frames 6x Child	40 frames 7x Child	44 frames 7x Child	48 frames 8x Child	44 frames 8x Child	44 frames 8x Child	40 frames 8x Child	32 frames 8x Child	32 frames 8x Child

Laser cannon / Big Core laser speeds (Measured in pixels per frame)

	Difficulty Value
	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Original	2.00	2.00	2.00	2.25	2.25	2.75	2.75	2.75	3.25	2.75	3.00	3.50	4.50	3.25	4.75	4.75
Altered	2.00	2.00	2.00	2.25	2.75	3.00	3.50	4.00	4.50	4.50	5.00	5.00	5.50	6.00	6.00	6.75

Bonus Life Settings
The score thresholds for extra lives are higher in nemesis:

	Bonus Life Dip Switch Setting
	Easiest	Easy	Hard	Hardest
Original	20,000 Every 70,000	30,000 Every 80,000	20,000 only	30,000 only
Altered	50,000 Every 100,000	30,000 only	50,000 only	100,000 only

Enemy Layout Changes
There are a few changes in enemy placement in Stages 1 to 3.

Original	Altered

At the start of the main area of Stage 1, there's an extra Uros enemy on the ceiling.

Original	Altered

Three extra Ducker enemies are on the ceiling in the middle of Stage 1.

Original	Altered

The last enemy section before the large rock wall in Stage 2 has nine green and seven red Dee-01 enemies in the original game. nemesis removes two of the red Dee-01s, meaning there's less opportunity for power-ups, adds three more green Dee-01s, and places more of them at the bottom of the area.

Original	Altered

The very start of Stage 3 is much more populated in nemesis, with three orange and four normal Garun ships. Three of the four Garun enemies on the right were removed, and the remaining one was repositioned.

Original	Altered

Two more Mother enemies were added to this area in nemesis, bringing the grand total up to three. The last three Garuns were deleted.