TASVideos

Tool-assisted game movies
When human skills are just not enough

Bisqwit / Initial Wiki Pages / Common Tricks

Common tricks

There are several tricks that can be used (or at least tried) in many games to improve the time.
If you are doing a movie, be sure to try every one of them :)

Close approach collision abuse

Games don't do collision checks like an eye does. You can often touch and even go partially inside the enemies without getting hurt.
See the SMB1 / Solomon's Key movies for examples of this.

Fast motion collision abuse

Games don't interpolate motion - motion means that you are in one place and next in some other place. This is how animation works.

If you are moving very fast, you can sometimes go through objects, because the game does not see a frame when you are inside the object. Combined with the close approach collision abuse mentioned above, the speed may not even need not to be very high.
See the Gradius movie for examples of this.

Other collision abuses

Using the above mentioned collision tricks may sometimes get you inside an object. This may be harmful, but it might also open you routes that are normally not accessible - for example, you might be able to gain support and jump from a vertical solid wall. See SMB1/SMB2j movie for examples of this.

In most games, if your character for some reason goes inside a wall, the game scrolls automatically your hero horizontally inside the wall until it finds a place where the hero can exit from the wall.
This happens, because the authors have been aware that collision checks aren't always perfect, and they wanted to make sure that the player doesn't get stuck.
This obviously allows you to get some handy shortcuts in some games. Look at the SMB3 / Rockman 2 movies for examples of this.

Invulnerability abuse

There are certain scenes in most games when your character is invulnerable. This usually happens when the game has started a preprogrammed demo that may not be interrupted - like the animation for finishing the level. If your character hits a pool of lava or something else that potentially kills you, the game may very well ignore your potential death and let you continue like you didn't die.
See the Little Nemo / Gremlins 2 movies for examples of this.

Pause abuse

In some games, pause is not very perfect:
  • In Mega Man, pause forces collision checks to be rerun, allowing monsters to get damage twice from the same shot
  • In Mega Man 2, pause resets gravity-accelerated speed counters to 0, which might allow moving in ways that were not meant.
  • In most games, pause creates a soundeffect that momentarily disables a sound channel from music.
  • If some scene has a precomputed length and/or is synchronized with the music, using pause may break the scene in some ways

It might be worthwhile to observe what anomalities does pause cause in your game.

Luck abuse

Video game consoles are actually computers.
All computers are simply just calculators - they do exactly what they have been told, and no matter how many times repeated, they always get the same results.
For this reason, there is nothing random in the games.
The games are pseudorandom.

Most games give you bonuses apparently randomly - there might be a 40% probability that you gain a heart from a skeleton you kill.
Observe:

  • Every time you replay that movie, you get the same result from that same location.
  • Every time you play and kill that skeleton, you get a random result from that same location.

The only source of "true" randomness for games is you.
The game is purely deterministic.

Learn to abuse this. You can affect anything that has randomness in it, by giving the game different input.
You can have perfect luck if you want!

Common sources of randomness:

  • Keys you happen to be pressing
  • Your timing

The results may be decided:

  • The last moment when they are needed (when the bonus is supposed to appear)
  • The moment of a state shift (when you kill an enemy and a bonus begins to formulate)
  • When you enter the scene (and the objects are created)

This means that sometimes you can experiment by doing different dances just before the enemy dies, and sometimes you have to experiment by entering the room from different angles.

Monster hit abuse

When games are designed, the maps are usually tested so that the character can't go where he should not go.
What they often haven't thought, is that the character may gain extra movement from monsters when they hurt you.
By getting hurt in a right place you can access routes you shouldn't.
Look at the Castlevania and Ghosts'n Goblins movies for examples of this.

Super speed abuse

When you act eyeblindingly fast, you might do things faster than the game developers have thought - for example, kill a boss before it goes serious.
See the Simon's Quest movie (last boss) for an example of this.

Too many objects abuse

This is actually a reverse abuse.
In many games, having too many on-screen objects simultaneously causes the game to slow down. When doing timeattacks, it might be a good thing to ensure things don't slow down.
The slowdown usually affects your character too, so it doesn't have benefits.

Untested code abuse

Try to do something that most probably hasn't been tested, like pressing left+right at the same time or up+down at the same time. It might do something nasty in the game.
Note that VirtuaNES doesn't allow you to do it, but that's not a reason to not try it on real NES / some other emulator.


Combined RSS Feed
Bisqwit/InitialWikiPages/CommonTricks last edited by Bisqwit on 2018-05-06 00:08:28
Page info and history | Latest diff | List referrers | View Source