Ikari_Warriors_(NES)

Level by level description

Level 1

Foot to tank - https://www.youtube.com/watch?v=mfIetUyC1aQ
If you start speedrunning this game, you'll see this section many times. This is where it becomes apparent that the game's rng must be fairly primitive. The enemy movements are clearly intended to be random, but you'll soon be able to correctly predict many of the movements. There are still many possibilities, so they will not be listed here.

Tank to foot - https://www.youtube.com/watch?v=p0SzRGjiPX4
The F and L are absolute requirements for the rest. The S is a nice to have, but not at all necessary. The first part of this tank is plagued by random grenade thrower spawns. They should only occasionally be able to hit you, but they're still an annoyance. The rest of the section is mainly to hope for not late tank spawns because of the sprite limit and getting the timing down to take out the gate guards without touching the gates. The shots during the last stretch before leaving the tank was to take all enemy soldiers approaching. If not, they will approach from behind and catch up with you while you're in the water on foot.

https://www.youtube.com/watch?v=BcwUzhX_2Uo
There are only four enemies you need to care about here. They are all best taken care of with grenades as shown here. The first one is a machine gunner that will also home in on you. The next two are self-exploding guys and the last is the rapid machine gunner right before the helicopter. Maybe 5-10% of the time, the mine will kill you if you walk in a straight line. If you want to reduce that risk (at the cost of a few frames) you can slightly to the left when you're walking alongside it.

Helicopter/flying glitch to the end - https://www.youtube.com/watch?v=ylCHMOPwtU8
The flying glitch is described in the Game Mechanics section. Right before the end of the level, you teleport a bit forward. It's also possible to teleport backwards. This glitch hasn't been researched, so the details are not understood. However, if you leave the helicopter as early as possible, you'll get the forward teleportation near the end, which saves a few seconds.

Level 2

https://www.youtube.com/watch?v=xpPSTUHsQVc
https://www.youtube.com/watch?v=yuFOPXwJbbw
https://www.youtube.com/watch?v=UGAJAzgaTPU

Level 3

https://www.youtube.com/watch?v=-eGQLme7jFM
https://www.youtube.com/watch?v=mKlgpH833vA
https://www.youtube.com/watch?v=JdMkAsrR8xc
https://www.youtube.com/watch?v=hL9fAFnx5II
https://www.youtube.com/watch?v=YWbME65q8XU

Level 4

https://www.youtube.com/watch?v=P86cpDuYzw0
https://www.youtube.com/watch?v=DYI-ShDF8dk
Foot to helicopter - https://www.youtube.com/watch?v=oqtI-QI1LE0
Random enemies can appear on the left side of the water section, but can quite easily be dealt with when it's the case. The rest is not random quite easy to execute. The route through the barrel area can be done faster and the big loop back before the helicopter obviously consumes a lot of time. However, from testing, this seems to give quite good chances for a fuel can drop near the helicopter. This has purely been tested by experimenting with various routes from various save states, but there is no hard proof that this optimizes the chances for the right drop. The drops contained inside the walls are determined a little before they appear on screen. By turning around and walking backwards, it's quite evident that the memory gets more and more corrupted. That's where the idea of the loop back comes from.

Helicopter to the end - https://www.youtube.com/watch?v=hCg_4BE0B0E
The last "missile turret" is very random and quite "intelligent" (moves in ways to avoid your shots), so care has to be taken here. The rest is fairly easy to execute. However, there is a small chance that weird things happen along the way. It can be enemies that spawn in slightly different locations and therefore being out of reach or a grenade that is tossed from one the walls that can hit. This is rare though. The route shown here is made to be as safe as possible (it's possible to take a straighter route at the cost of some risk), but it's still not 100% safe.