Verge doesn't use ASCII for reading and comparing keyboard input, but instead uses the keyboard scan codes instead. You will generally only use the scan codes when reading lastpressed or the key array.
EX:

if(key[SCAN_ESC]) exit("");
else if(key[SCAN_ENTER]) map("town.map");

or

switch(lastpressed){
case SCAN_EXIT: exit("");
case SCAN_ENTER: map("town.map");
}

from vergec.txt:
{"SCAN_ESC", "01" }
{"SCAN_1", "02" }
{"SCAN_2", "03" }
{"SCAN_3", "04" }
{"SCAN_4", "05" }
{"SCAN_5", "06" }
{"SCAN_6", "07" }
{"SCAN_7", "08" }
{"SCAN_8", "09" }
{"SCAN_9", "10" }
{"SCAN_0", "11" }
{"SCAN_MINUS", "12" }
{"SCAN_EQUALS", "13" }
{"SCAN_BACKSP", "14" }
{"SCAN_TAB", "15" }
{"SCAN_Q", "16" }
{"SCAN_W", "17" }
{"SCAN_E", "18" }
{"SCAN_R", "19" }
{"SCAN_T", "20" }
{"SCAN_Y", "21" }
{"SCAN_U", "22" }
{"SCAN_I", "23" }
{"SCAN_O", "24" }
{"SCAN_P", "25" }
{"SCAN_LANGLE", "26" }
{"SCAN_RANGLE", "27" }
{"SCAN_ENTER", "28" }
{"SCAN_CTRL", "29" }
{"SCAN_A", "30" }
{"SCAN_S", "31" }
{"SCAN_D", "32" }
{"SCAN_F", "33" }
{"SCAN_G", "34" }
{"SCAN_H", "35" }
{"SCAN_J", "36" }
{"SCAN_K", "37" }
{"SCAN_L", "38" }
{"SCAN_SCOLON", "39" }
{"SCAN_QUOTA", "40" }
{"SCAN_RQUOTA", "41" }
{"SCAN_LSHIFT", "42" }
{"SCAN_BSLASH", "43" }
{"SCAN_Z", "44" }
{"SCAN_X", "45" }
{"SCAN_C", "46" }
{"SCAN_V", "47" }
{"SCAN_B", "48" }
{"SCAN_N", "49" }
{"SCAN_M", "50" }
{"SCAN_COMMA", "51" }
{"SCAN_DOT", "52" }
{"SCAN_SLASH", "53" }
{"SCAN_RSHIFT", "54" }
{"SCAN_STAR", "55" }
{"SCAN_ALT", "56" }
{"SCAN_SPACE", "57" }
{"SCAN_CAPS", "58" }
{"SCAN_F1", "59" }
{"SCAN_F2", "60" }
{"SCAN_F3", "61" }
{"SCAN_F4", "62" }
{"SCAN_F5", "63" }
{"SCAN_F6", "64" }
{"SCAN_F7", "65" }
{"SCAN_F8", "66" }
{"SCAN_F9", "67" }
{"SCAN_F10", "68" }
{"SCAN_NUMLOCK","69" }
{"SCAN_SCRLOCK","70" }
{"SCAN_HOME", "71" }
{"SCAN_UP", "72" }
{"SCAN_PGUP", "73" }
{"SCAN_GMINUS", "74" }
{"SCAN_LEFT", "75" }
{"SCAN_PAD_5", "76" }
{"SCAN_RIGHT", "77" }
{"SCAN_GPLUS", "78" }
{"SCAN_END", "79" }
{"SCAN_DOWN", "80" }
{"SCAN_PGDN", "81" }
{"SCAN_INSERT", "82" }
{"SCAN_DEL", "83" }
{"SCAN_F11", "87" }
{"SCAN_F12", "88" }


Be warned that the values for Insert, Delete, Home, End, PgUp and PgDown listed here are for the numpad keys. The "real" versions are 210 (INSERT), 211 (DELETE), 199 (HOME), 207 (END), 201 (PGUP), and 209 (PGDN). You will need to define these yourself if you want to use them without entering the values directly.