final overhaul that should make everything work

Redid chapter names, sourced from the source snoot script
Tightened up transitions in chapter select
made all get_ending() checks use ending_route_number instead.

game/src/chapter_select.rpy

@@ -13,28 +13,28 @@ define chapter_tuple = [
 ]
 
 define ending_1_tuple = [
-    ("11.5. Announcing a Plan", "chapter_11A") # this is supposed to be ch 12 (13, accounting for ch 5), but it somehow got counted as part of 11 internally
+    ("11.5. Announcing a Plan", "lPromAnnouncement"), # this is supposed to be ch 12 (13, accounting for ch 5), but it somehow got counted as part of 11 internally
     ("12. Let's all go to the Museum", "chapter_12A"),
     ("13. Prom is Complicated", "chapter_12_5D"),
     ("14. Bowling for Volcano High", "chapter_14A")
 ]
 
 define ending_2_tuple = [
-    ("11.5. Announcing Nothing Important", "chapter_11B")
+    ("11.5. Announcing Nothing Important", "lPromAnnouncement"),
     ("12. Let's all go to a Concert", "chapter_12B"),
     ("13. Prom is For Suckers", "chapter_13B"),
     ("14. Anon and the Infinite Sadness", "chapter_14B")
 ]
 
 define ending_3_tuple = [
-    ("11.5. Announcing a Date", "chapter_11C")
+    ("11.5. Announcing a Date", "lPromAnnouncement"),
     ("12. Let's all go Camping", "chapter_12C"),
     ("13. Prom is Suprising", "chapter_12_5C"),
     ("14. Volcano Highschool Musical", "chapter_14C")
 ]
 
 define ending_4_tuple = [
-    ("11.5. Announcing a Show.", "chapter_11D")
+    ("11.5. Announcing a Show.", "lPromAnnouncement"),
     ("12. Let's all go to the Aquarium", "chapter_12D"),
     ("13. Prom is Memorable", "chapter_12_5D"),
     ("14. Fast Times at Volcano High", "chapter_14D")
@@ -60,7 +60,7 @@ label chapter_select:
     stop music1
     stop music2
     scene black
-    with dissolve
+    with Dissolve(0.25)
 
     jump chapter_select_go_back # Technically we don't need to explicitly jump to the label just below here, but doing so anyway for clarity
 
@@ -78,7 +78,7 @@ label chapter_select_go_back:
         "Ending 4":
             $ ending_route_number = 4
         "Exit to main menu":
-            scene black with dissolve
+            scene black with Dissolve(0.25)
             return
     
     window hide
@@ -88,7 +88,7 @@ label chapter_select_go_back:
 
 init python:
     def select_chapter():
-        global current_chapter, quick_menu, ending_route_number, chapter_list_index
+        global current_chapter, quick_menu, ending_route_number, chapter_list_index, chapter_list, ending_chapters_determined, chapter_list_length
 
         ending_tuples = {
             1: ending_1_tuple,
@@ -98,7 +98,7 @@ init python:
         }
 
         # Chapter list to select from
-        chapter_tuples = chapter_tuple + ending_tuples{ending_route_number}
+        chapter_tuples = chapter_tuple + ending_tuples[ending_route_number]
 
         # Vars for displaying the choices
         chapters_per_page = 6
@@ -110,7 +110,7 @@ init python:
         # The loop that displays the chapter choices
         while True:
             # Displays the choices
-            selected_tuple = renpy.display_menu(chapter_tupless[start_index:end_index] + [("Next Page", "next_page"), ("Go Back", "chapter_select_go_back")])
+            selected_tuple = renpy.display_menu(chapter_tuples[start_index:end_index] + [("Next Page", "chapter_select_next_page"), ("Go Back", "chapter_select_go_back")])
 
             if selected_tuple == "chapter_select_next_page":
                 # If we're at the last page, wrap around to the first
@@ -120,20 +120,36 @@ init python:
                 end_index = min(start_index + chapters_per_page, len(chapter_tuples))
 
             elif selected_tuple == "chapter_select_go_back":
-                renpy.jump(chapter_select_go_back)
+                renpy.jump("chapter_select_go_back")
 
             else:
                 break # We've selected a chapter
         
-        chapter_list += ending_routes{ending_route_number} # Actual chapter list for the game to run
-        current_chapter = selected_tuple
+        setup_ending(ending_route_number)
+
+        store._window_auto = True
 
         # Find the index position of the selected chapter
         try:
-            chapter_list_index = chapter_list.index(current_chapter)
+            chapter_list_index = chapter_list.index(selected_tuple)
         except ValueError: # This crashes the game otherwise since it wouldn't find the correct chapter
-            MainMenu(confirm=False) () # Exits to the main menu
+    
+            # Make an exception for the 11A/B/C/D chapters, since we're technically supposed to start at the PromAnnouncement label
+            # Stank as fuck
+            if selected_tuple == "lPromAnnouncement":
+                chapter_list_index = 10
+                current_chapter = "chapter_11"
 
+                toggle_debug()
+                quick_menu = True
+                renpy._window_auto = True
+
+                renpy.jump("lPromAnnouncement")
+            else:
+                print("No such chapter exists!")
+                MainMenu(confirm=False) () # Exits to the main menu
+
+        current_chapter = selected_tuple
 
         # Start playing the game
         toggle_debug()