A possible summary is:
This is a story of a soldier's experience in a trench warfare assault during World War I. The soldier describes the horrors of crossing no man's land under enemy fire, the dangers of mud, gas, and barbed wire, and the brutal hand-to-hand combat in the enemy trench. The soldier survives the attack, but has to face a counterattack from the Germans with the help of inexperienced reinforcements. The story ends with a plug for another video about military combat.
Here are some possible key facts extracted from the text:
1. The text is about a soldier's experience of a trench assault during World War I.
2. The soldier survived a poison gas attack, a machine gun barrage, a mortar shelling, and a hand-to-hand combat in the enemy trench.
3. The soldier lost his boot, his canteen, and his rifle during the assault, but managed to find replacements.
4. The soldier killed a German soldier with his knife after a brief moment of hesitation.
5. The soldier was joined by reinforcements who were inexperienced and had to defend the trench from a counterattack.