Quick answer: GameMaker keyboard_string skipping characters when player types quickly? GM polls input per step; fast typists exceed step rate - listen for individual key events instead.
Player types 'inventory' in chat; receives 'invntry'. Some keystrokes dropped.
Use Keyboard Up event
One event per keypress; never skipped. Build the string by appending characters in the Keyboard Up handler.
Or read keyboard_lastkey
keyboard_lastkey updated per step. Append to your buffer; clear after read. Less reliable than events but works at moderate typing speed.
Test with a fast typer
Get someone who types 100+ wpm. Their typing surfaces bugs touch-typists at 60 don't.
“Polling-based input loses fast events. Event-based input doesn't.”
For chat input, use the OS-level text input event. It handles modifiers, IME, multi-byte properly; rolling your own misses cases.