I'm wondering is someone could do the longplays of X-COM UFO Defense and X-COM Terror from the Deep using OpenXcom. OpenXcom is an open-source port of those two games on PC that have a few changes and many bug fixes. Eino replied to a comment that it should be ok to use OpenXcom as long as you don't modify the gameplay much.

A few changes from vanilla:
1. Transport Crafts have no item limit. Instead, items stored on crafts still count towards storage space. (optional)
2. Memorial Screen: accessed from soldiers area, this lists the soldiers who died in the fight against the alien menace. Through the memorial, you can check statistics of the game.
3. Multiple Radar installations provide increased chance of UFO detection (Small Radar is not rendered obsolete by large radar). Hyperwave decoder still renders radar installations obsolete.
4. When a UFO is detected, you have the option to intercept it immediately.
5. Option to set workshop for infinite production and for the product to be sold upon completion.
6. Used clips have their ammo totaled so after the rounds are dispersed among used clips, any remaining is lost.
7. Various game settings, such as force-fire option, force craft launch (bypass repairs, refueling, and reloading), and alien bleeding (fatal wounds can apply to certain aliens)
8. Soldiers on battlescape can be colored to resemble those from inventory screen.
9. Terror missions now have both male and female civilians.

Sorry, I don't remember details of this conversation. Maybe it was a comment I replied in YT? I probably said something that unofficial bugfixes should be OK unless those modify the original game.

The original game has some stupid bugs you just learnt to live with, for example floaters can fly and hide in places where you can't reach them and the only option is to either abandon or restart the mission. Another one is about ammo clips. Those get fully consumed if the weapon is fired during a mission and if the weapon isn't unloaded before finishing the mission.

I've now checked OpenXcom and it does modify the original game even if no Mods are enabled. Like the unlimited item space in Skyranger as you mentioned. The other one I noticed immediately was about radar range becoming visible when building bases.

So even if you feel some of the modifications would've been nice to have in the original release, those were not. Anyways, I don't make the rules here and this stuff should be checked with the admins before recording.

Most of those changes made from OpenXcom are optional so it can be turned off if not allowed for a longplay.