A possible concise summary is:
The speaker introduces the video as a game theory episode about Undertale, where he tries to solve the mystery of WD Gaster, the missing royal scientist. He thanks the viewers for their support and apologizes for making the theory a three-parter. He then presents his main claim that Gaster is actually split into two characters: Sans and Papyrus. He supports his claim with evidence from the game's fonts, dialogue, lab entries, and secrets. He also explains how Gaster's experiment with determination caused him to shatter across time and space. He ends the video by teasing the next episode where he will reveal more about Papyrus and the neuroscience of Undertale. He also invites the viewers to watch his live stream where he plays fan-made battles against Gaster.
Here are the key facts extracted from the text:
1. A papyrus made a pun about spaghetti.
2. The speaker expressed gratitude for support received after a personal Undertale series episode.
3. The speaker acknowledged and thanked individuals who apologized for negative comments they had previously made.
4. Gaster was a royal scientist who fell into his creation and was shattered across time and space.
5. Alphys conducted experiments with determination on comatose monster bodies.
6. The experiments resulted in the creation of amalgamates, monsters fused together by determination.
7. Sans and Papyrus appeared in Snowden one day without explanation.
8. Entry number 17 from the lab entries is missing and is written in Wingdings font.
9. Sans has knowledge of other timelines and possesses space-time manipulation abilities.
10. Papyrus's origin is mysterious, and there are implications he may be connected to Gaster.
Please note that these are brief summaries of the facts presented in the text, and the context or additional details surrounding these facts have been omitted for brevity as per your request.