Horses can no longer be pushed over fences that have carpets on top.
The archive unpacked into a single executable: Minecraft 11951 (32-bit).exe . No jar file. No launcher. Just a glowing green icon that looked like a dirt block with one pixel missing. minecraft 11951 de 32 bits link
What and RAM amount does your system currently have? Are you trying to play Java Edition or Bedrock Edition ? Horses can no longer be pushed over fences
https://piston-data.mojang.com/v1/objects/1b557c3db9b48cff90c7c2c32f5ec0d62b66c80e/client.jar minecraft 11951 de 32 bits link
Use the official launcher on desktop platforms to manage game versions securely.