A possible concise summary is:
The speaker is playing a game called Subnautica, where he is stranded on an alien water planet. He decides to build a base near the Aurora, a crashed spaceship, and uses a terraformer tool to create a tunnel from the surface to the depths. He also makes an observatory, a sign, and a room with an aquarium. He encounters some dangers and glitches along the way, but he is proud of his achievement. He plans to explore new biomes in the next episode. He thanks his viewers for watching and asks them to like and subscribe.
Here are the key facts extracted from the text:
1. A nuclear fusion reaction was sustained at temperatures over 100 million°C for 30 seconds.
2. The experiment achieved a net energy gain.
3. The temperature achieved is nearly seven times hotter than the core of the Sun.
4. The core of the Sun has a temperature of about 15 million Kelvin.
Please note that these facts are based on the information provided in your text and should be verified for accuracy.