Part 4:
"Los tentaculos a la muchacha" is not translated.
When saving Weena, and going straight into the dome afterwards, the text says that "Weena accompanies you", but she does not do that before speaking to her and selecting "come with me".
When at mountain wall with huge closed stone door, you can select "East" and "Este". "East" will give you the GL264 code, while "Este" will take you east.
You always hit a stalactite, which there is none of, when trying to throw the grenade.
Part 5:
When dying "Codigo XX" for part 5 is not translated.
When going down to the gigantic cauldron at the beginning, Weena is there, but isn't she locked up, and first assumed to be there the second time you go there ??
Every time using the M15 you are wrongly told that there are 0 bullets left.
You keep having the grenade in the inventory after this has been used.
When coming up from rope down to the lava "Oeste" is not translated, and when going west right before big earthquake "Oeste" is not translated again.
At the place with the gigantic cauldron for the second time, you get back to the stairs where you got the key. If you go up the stairs and then west, then the road will not be blocked, and the earthquake will come again.
At the end there are 2 x "You get on the machine". In the first Weena comes between, and in the second you get on the machine.
Epilogue:
Leonardo DaVinci: "Donót" should be "Do not"
At 1899 "retrocediendo" is not translated.
28 October 1898: "werenót" should be "were not", and on the next page "youúve" should be "you've"
23 October 1898: "itús" should be "it's"
"Leslie was recovering....I knew then that "she".." <-- "she" should be "I"
Dr. Preston: "I canút..." should be "can not"
When knocking at the door "Davyd" should be "David"
Leslie: "...which is how long Iúve been sick" should be "I've"
Final / Del juego: "he future" should be "The future"