Ikari Warriors 2/Game Mechanics
From SDA Knowledge Base
Some observations regarding movement speed
All levels go from bottom to top of the screen so it's important to keep the vertical movement speed up as much as possible. Below ratios are with respect to the vertical speed.
Diagonal/Straight flying speed ~76%
Diagonal/Straight walking speed (land) ~72%
Diagonal/Straight walking speed (water) ~69%
Straight walking (land)/flying speed ~68%
Straight walking (water)/walking (land) speed ~68%
In practice, as an example, this means that a quick twitch diagonally right (or left) to shoot an enemy when walking on land incurs a time loss of roughly 3-5 frames.
Galago tunnels
The Galago tunnels are the passages between levels. They can either be filled with weapons or enemies. It's obviously best if they are filled with weapon items... However, it's not fully understood what determines this. Below are some empirical observations.
- A test consisting of 10 playthroughs of the first level resulted in monsters in the tunnel 5 times.
- By entering the tunnel from a save state "close" to the entrance, you'll always get the same result (the same is true for all levels). By starting from a save state further and further away, you'll eventually start to sometimes get monsters, sometimes weapon items. A more detailed study would clearly be needed to determine the exact trigger and if it's something that can be manipulated in real-time.
- The second tunnel seems to always be the same as the first tunnel (so if there are monsters in the first tunnel, there will be monsters in the second tunnel as well).
- A test consisting of 10 playthroughs of level 3 resulted in monsters 9 of the times if there had also been monsters in the level 2 tunnel. The same test, but from a save state without monsters in tunnel 2 only gave monsters once.
- A test consisting of 10 playthroughs of level 4 resulted in monsters 6 of the times if there had also been monsters in the level 2 tunnel. The same test, but from a save state without monsters in tunnel 3 gave monsters 4 times.
In summary, the first tunnel seems to be a 50/50 chance and at the time of writing this it's not known if this can be manipulated. There is a very high probability that tunnel 2 and 3 will have the same content as level 1. Level 4 seems to be more random, but maybe with slight preference for the same content as in the previous levels. All of the playthroughs in the tests above used the speedrun route and were played on emulator. However, the play quality varied quite a bit, so it's impossible to say what determined monsters in the tunnels. The tests do however correspond very closely to the general hunch gained from speedrun attempts on console.
It's possible to get through the first three tunnels unscathed with only minor time losses compared to when there are no monsters. There hasn't been found a way yet to get through tunnel 4 when it's filled with monsters though.
1st tunnel - http://www.youtube.com/watch?v=R2sC4KABllc
2nd tunnel - http://www.youtube.com/watch?v=U60P6yoW9aU
3rd tunnel - http://www.youtube.com/watch?v=ldFa-nxpJg4
Weapons
Switching weapons costs roughly 1.5 seconds (provided you've already planned a trip to the menu). While the boomerangs are incredibly overpowered, they don't save anywhere near that time any place in the game. The bazooka and the sword are somewhat interesting to play with casually, but have no impact in a speedrun. The mines are rubbish. The fastest way is simply to play with the machine gun (B-button) and the grenades (A-button) the whole game. All weapons can be upgraded three times by collecting the respective weapon tokens (longer reach, bigger explosion area etc). The effects of upgrading the weapons make no difference in a speedrun though.
