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Tool-assisted game movies
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Submission #6553: scrimpeh's NES Power Blade in 13:54.01

Console: Nintendo Entertainment System
Game name: Power Blade
Game version: USA
ROM filename: Power Blade (USA).nes
Branch:
Emulator: BizHawk 2.3.0
Movie length: 13:54.01
FrameCount: 50123
Re-record count: 51692
Author's real name: JPT
Author's nickname: scrimpeh
Submitter: scrimpeh
Submitted at: 2019-11-30 22:07:24
Text last edited at: 2019-12-10 02:02:11
Text last edited by: Dacicus
Download: Download (15251 bytes)
Status: published
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Author's comments and explanations:
Power Blade is a Platformer for the NES, released by Taito in 1992. In the game you take control of NOVA, who is tasked to destroy a maverick computer with a boomerang. This movie aims to improve Aglar's 2009 run, saving about 90 seconds over the previous run from new glitches and routing.

Game objectives

  • Emulator used: BizHawk 2.3.0, QuickNES Core
  • Aims for fastest time
  • Takes damage to save time
  • Uses L+R / U+D
  • Genre: Action
  • Genre: Platform


(Link to video)

Temporary Encode for your viewing pleasure

Comments

Power Blade is a great and original game for the NES which is in no way derivative of any popular culture or similar games of the time. You take control of Not-Arnie who destroys killer robots by hurling flaming bananas at them. And bats. Somehow these games always have bats. The game is split up into six stages which you can complete in any order, similar to Mega Man. After you beat all stages, a final seventh stage is unlocked which contains the final boss. In every stage, before facing the boss, NOVA needs to find a contact which gives him an ID card to open the boss door. This makes the levels fairly nonlinear, and routing a large concern of the run.

To contend with his foes, NOVA gets a boomerang, which can be upgraded several times to be more effective. When you throw a boomerang, its power depletes and needs a few frames to recharge. During that time, its range and speed is reduced. I need to make sure I have the right amount of power at the moment I need to throw a boomerang. Additionally, you can jump over or duck under returning boomerangs, sometimes making it possible to hit enemies behind you. Nova has to stand still and go through an animation when throwing boomerangs, but it can be interrupted by ducking or jumping. Additionally you can pick up grenades from enemies, which act as a one-time consumable screen clearing item with a few surprise applications noted below. In every level, there's one or two Power Suits hidden, which gives NOVA three extra hitpoints and a higher-damage attack that goes through walls. It is essential to pick this suit up at some point, as it makes certain boss battles significantly faster

I was looking for a while for a game to TAS, and eventually came across Power Blade. While messing around with the game, I noticed a few Up + Down glitches with ladders, which made me decide I wanted to TAS this game. The new glitches allow for large shortcuts, significantly changing the route in many of the stages. In the end, I save 9015 frames over Aglar's run, or just over 90 seconds.

Tricks

Grenade Buffering

This glitch is incredibly simple to perform casually. When entering a boss door, press the Grenade button, and the boss goes asplode. This doesn't work for some reason with the Stage 3 or Stage 6 bosses, nor the final boss. The Stage 3 boss and the final boss are immune to grenades entirely, the Stage 6 boss cannot be oneshot. I legitimately do not know what some of the other bosses in this game even look like.

Instant Ladder Climb (New!)

At the top of a ladder, NOVA pulls himself up, similar to Mega Man. By pressing U+D at the top of the ladder, this animation is skipped, saving 7 frames each time it's done.

Ladder Warping (New!)

If you press U+D while on the ladder at the very top of the screen, several interesting things can happen. NOVA moves up into the screen above, but the game also thinks he climbed down the ladder onto the bottom tile of the previous screen. Depending on what tile was at the bottom of the screen in the previous room, several things can happen:

  • If the tile was air, NOVA will start in the air in the next screen

  • If the tile was spikes, NOVA will touch them and die

  • If the tile was a ladder, NOVA will still be on a ladder in the next screen

  • If the tile was solid, NOVA will be on the ground in the next screen. This is where things get interesting. He can move back and forth on the tile and jump from it. If you press down, NOVA will climb down the ladder, wrap around vertically, and end up at the top of the screen. From there, NOVA can drop down into the screen, or climb up further to end up in the screen above. This allows scaling vertical sections extremely quickly and significantly subverts many of the stage designs, provided the tiles are laid out right.

This only works when NOVA is centered on the ladder, for some reason.

Ceiling Clips

At an outer edge between a ceiling and a wall, NOVA can jump into the ceiling, and if his positioning is right, clip into the ceiling. This works with ceilings that are 2 and 3 blocks high. From there, NOVA can further scale the wall by jumping.

Grenade Phasing (New!)

When using a grenade or a ration while moving, NOVA is moved one pixel in the direction he was going, ignoring any walls or pits in his way. Using three grenades, it is possible to get far enough into a wall to clip into it. With infinite grenades, it would theoretically be possible to phase through any wall, or move over any pit. Unfortunately, you can only ever hold 4 grenades at a time.

Item Drops

Given how many tricks in the game rely on grenades, and how useful grenades are in general, getting as many grenades as possible is crucial for the run. You can only get grenades from enemy drops. All enemy drops are fixed and based on a 64-entry table which is indexed by the total number of enemies killed. The drops are listed in the table below:

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0 Boomerang Up Range Up Grenade Star Boomerang Up Burger
16 Star Grenade Boomerang Up Star Power Up Burger
32 Boomerang Up Star Power Up Star Burger
48 Power Up Burger Star Power Up Grenade Power Up Range Up Burger

As you can see, I only get 3 grenades every 64 enemies killed. Since the shortcuts also mean I kill significantly fewer enemies along the way, this puts the entire run on a significant crunch for grenades. An enemy kill is only counted when the explosion finishes, so leaving the screen too early may mean that a kill doesn't count. Enemies may not always be placed conveniently to pick up their drops either, so sometimes, I need to forego killing an enemy because it would drop an important item, but I cannot reach it.

I also get 5 Burgers per drop cycle, making health routing subject to similarily stringent requirements. You must always finish a stage with full HP, because otherwise, the stage takes an additional 48 frames to end after the health recharge animation.

Stage by stage comments

Sector 1

In this stage, I need to acquire all my power-ups for the rest of the game. Right away, I use the ladder warp to jump from the bottom of the second screen to the ledge. You need a perfect vertical subpixel position for this to work. I don't use the grenade on the ladder like Aglar does, because I need to save it for later. This means I'm forced to take damage and need to refill my life later. This also means I miss out on a boomerang drop, which kinda messes up my item route. I still manage to pick up the final Power upgrade by the end of the stage. In the second to last room, I deliberately keep a couple of bats on screen for a while to prevent a turret from spawning. The turret would otherwise shoot a tomato at me in an inconvenient spot. I also pick up a ration here which is used later. Not much else to mention about this stage. In total, 160 frames were saved in this level.

Sector 2

This stage features the first significant route change of the run. Instead of going the upper route, I go the lower route, using a ladder warp to quickly reach the contact. This route forces me to take damage from a floor monster, and also forces me to go through the crusher section twice. By hitting the crushers with boomerangs, it is possible to briefly stun them, making it possible to jump under them. The hit detection on boomerangs is pretty finnicky, as boomerangs only check for damage on every other frame. Taking damage is highly undesirable in this section, because NOVA always jumps with maximum height when he has hit invulnerability, which means he often jumps against ceilings. On the way back, I can take damage, since there's fewer walls in my way, and a health recharge happens to drop conveniently right afterwards.

There's a secret wall at the end of the level which acts as a shortcut. All in all, 1080 frames were saved in this stage.

Sector 3

This stage shows how effective ladder warps are in climbing the levels vertically. I save a large amount of time in reaching the contact. I cannot help but take damage twice from the nuclear waffles, since there is no way to affect them. This room is also prone to lag if you use your boomerang. I also cannot kill any enemies here because I'm waiting on a convenient enemy for a grenade drop, which only happens several screens later.

The beehive boss was easily the most difficult part of the run, and the only place where RNG significantly factored into it. There's 4 beehives, which all open after a set amount of time. They close after 24 frames, but while they are in their hit invulnerability phase, their close timer is suspended. Therefore, it is possible to kill a beehive in one cycle. Each beehive has 16 HP, and a boomerang does 2 damage. However, it is not possible to spread out your damage enough to kill all beehives in one go. By throwing boomerangs in the right position, it is possible for a boomerang to linger over the hitbox of a beehive, hitting it up to 4 times, for 8 damage total. Additionally, I must make use of the recoil of a boomerang, hitting more than one beehive. Still, I must let the bottom beehive close on me once. It opens again after 1 - 256 frames, which is dependent entirely on RNG. The RNG in this game is based on the game's idle CPU cycles per frame, so it can be any value.

There is a lower bound on how fast you can kill the boss (the time it takes for the last beehive to open + the time it takes to drain its HP), which I just barely reach, matching Aglar's time. In total, 1014 frames were saved in this stage.

Sector 4

This stage features a significant shortcut which cuts out a large portion of the level. Overall, it is pretty straightforward though. At the end, there is no way but to take damage from a crawler. I use the ration I saved up from Stage 1 here, saving another grenade for later. 1820 frames were saved here.

Sector 5

Another short and fairly straightforward stage. The drop counter hits me very badly here, making me not able to kill several enemies, beecause I need another grenade. There's multiple routes I can go at the end of the stage, but using the leftmost ladder turned out fastest. I need to wait for 4 frames to make an enemy's bullets pass me. I don't know of any way to skip the wait. The exit door is approached the same way as by Aglar. 592 frames saved here.

Sector 6

I can go multiple ways here through the sewer section, but matching Aglar's route is fastest. Doing the ceiling skip under a 2 tile high gap is 2 frames faster than doing it the previous run's way. I also pick up the power suit here, grabbing it through the ceiling. This is the fastest place to get it, losing only 84 frames. The Power Suit's attack is ludicrously overpowered, and its hitbox is massive. I get the fourth and final grenade here, saving up every grenade I could have for the rest of the game. While the boss cannot get one shot by grenades, he still takes damage from them, so I use one here for a 16 frame save. Overall, 896 frames were saved here.

Sector 7

The final level of the game, and it's quite a doozy. This is what I've saved up all those grenades for. I can do a ladder clip into a room that is normally not accessed, which would lead to a significant shortcut, if there wasn't a problem that the next ladder is out of reach. By using three grenades, I can embed myself into the wall and use it as a platform to go to the next ladder. From there, I can do another ladder clip, skipping a huge section of this level, saving some 30 seconds. The final boss is entirely fixed, and speedwise identical to Aglar's run. With the final hit, it's gg, and the run is over. 2652 frames saved in this level.

Other comments

And that was Power Blade. I'm very happy with the tricks I found, and overall the movie was a lot of fun to make. Still, there's a few mistakes that can be improved:

  • I messed up during the ending section of Stage 4, before the platforms. I accidentally forgot to jump after throwing a boomerang, so I land on the ground while the animation is still active. I didn't catch that mistake until submission, losing 2 frames. I tried hexing it, but the run wouldn't sync.

  • Climbing up into a higher screen, if the ladder stops on the bottom tile of the screen, it is usually faster to use a ladder warp and jump, rather than just climbing the ladder normally. I didn't catch this until Stage 4, so earlier ladders might be improved this way.

  • When dropping down a ladder from the very top of the screen, you can save a frame if your Y subpixels are 248. I didn't catch this until Stage 4 also.

  • If you can kill about 20 more enemies until the beginning of Sector 7, you can get a grenade drop at the start of Sector 7, freeing up an extra grenade to be used against the Stage 6 boss. This allows saving 24 - 32 frames. Alternatively, if this is not possible, Sector 3 should be skipped until NOVA has the Power Suit. The bee boss fight can be completed 16 frames faster, and it is possible to tank the 2 hits from the waffles using the Power Suit, saving some ~9 frames from recharging. Discounting the 6 frames of extra cursor movement, this should be between 3 - 19 frames faster, depending on how many grenades can be used against the Stage 6 boss.

Nevertheless, I hope you enjoy watching the movie as much as I enjoyed making it. It feels good to be TASing again, even if I don't get all that much time for it anymore. I'd like to thank Aglar for making the old run, which served as an inspiration and reference for mine many times over. I'd also like to thank FerretWarlord and EZGames69 for their support. Special Thanks also go out to StarFighters76 for making these stage maps, which I used for routing a lot. With that, thank you all for making it this far, and if you have any questions, as usual, I'll be happy to answer.

Until next time

-scrm


Masterjun: Hello and welcome back to TASVideos! Judging.

Masterjun: Replaced file with one where a mistake is fixed (identical framecount).

Masterjun: Accepted to Moons as an improvement to the previous run.

Dacicus: Processing...


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