Verified browser emulators run the ROM directly. If a site asks you to download and run a .exe file to play, leave immediately.

To play Pokémon Red, you'll also need a ROM (Read-Only Memory) file. Make sure to download it from a reputable source:

In Pokémon Red, leveling up a Magikarp to Gyarados takes forever. Use the emulator’s (usually the spacebar or a speed toggle). You can run the game at 2x, 4x, or even 10x speed. This is only possible on modern web emulators.