This is how I have enabled the console and cheats.
Choose the bottle where Half-Life is installed
Browse for and Open the HL.exe
In the Command line after HL.exe" type in -console +sv_cheats 1
Then - Save Command to Programs Menu
Use this new alias for playing the game and the console and cheats will be enabled.
When looking at your steam games list right click on a game and choose properties. On the window that pops up you can select set launch options. You can from here enter any launch options you please such as -console, you can also make any console command automatically apply by typing it in the launch options with a plus in front of it i.e. +sv_cheats 1
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