Hi there! I'm really into these kinds of games, so I'm happy you're working on it!
Sometimes when I try to move a character, I get an error like this:
ERROR in
action number 1
of Step Event0
for object obj_control:
Unable to find instance for object index -4
at gml_Script_scr_player_turn
gml_Script_scr_player_turn (line -1)
gml_Object_obj_control_Step_0
Looking forward to the development of the game!!