This is a Boss Rush video featuring all the boss fights in Hallow's End, an EarthBound Romhack.

Hallow’s End is an intriguing romp through a Costume Quest-esque Halloween world filled with danger…and candy. Can you help Sally, Clyde, and Craig solve the problems in this strange world before school starts in the morning? Complete with new maps, enemies, items, and even music, this is one Halloween you won’t soon forget!

Source: https://www.romhacking.net/hacks/1876/

Timestamps:
0:00 Opening
2:10 Disciples of Azathoth
4:14 1st BOSS: Avatar of Azathoth
7:09 2nd BOSS: Noctus
10:32 3rd BOSS: Aphotic Aberration
13:42 Bomb-in-a-Box!
14:29 4th BOSS: Gnaw, King of the Sewers
17:32 Soulless Zombies
18:58 Trap Door
21:22 5th BOSS: Jenkins
25:22 Mereseti Guards
26:19 6th BOSS: Frostilicus
29:44 7th BOSS: Photo Guy
32:28 8th BOSS: Missingno. & 'M
36:23 The Botz Gang
39:10 9th BOSS: Miss Anna
42:02 10th BOSS: Miss Anna Crazy Mode!
45:57 11th BOSS: TitanimYynt
50:13 12th BOSS: The Boy
54:16 13th BOSS: Cops & Robo Officer
57:51 14th BOSS: Captain Strong
59:57 FINAL BOSS #1: Mara's Demon
1:09:19 Ending?
1:12:36 Post Ending Cutscene
1:13:49 FINAL BOSS #2: End of Hope
1:18:36 FINAL BOSS #3: End of Dreams
1:23:48 Actual Ending