In Day of the Tentacle, there are a number of glitches that allow you to skip about half of the game. Executing these glitches during a run will have a significant impact on the times you get.

Some of these glitches work in a different way depending on whether you're playing on ScummVM or on emulators like DOSBox. For the most part, this guide will be about playing the game on ScummVM. Part 12: differences between ScummVM and other platforms will be about these differences, while part 13: item slides and the quarters cutscene and part 14: non-ScummVM routes will deal with glitches and routes exclusive to these other platforms.

Huge shout-outs to swimfan, who found most of these glitches and caused a complete revolution in the way we speedrun this game.

Introduction

This guide is split in multiple parts. Some of these glitches are complex, so they deserve their own guide.

At the end of each of these parts, you'll find a more technical section explaining how these glitches work (titled "under the hood"). If you're a casual runner, you can skip these sections.

For now, let's start with the basics.

Summary

Here's a brief summary of things you can do that you're not supposed to do:

• You can switch to a different character during a conversation.
• You can gain control of your character during a cutscene.
• You can have two characters in the same room, and exchange items without the Chron-O-John.

The game doesn't expect you to be able to do any of these actions, so, when you do, well... unexpected things happen. For example, Hoagie might paint the tree, even if he doesn't have the red paint. Or Bernard might tie the rope around Ted's neck, even when the rope isn't there. Or Laverne might use the hamster with the generator in the future... even when she doesn't have the hamster, and you never picked up the hamster in the first place.

Hmmm... using the hamster without picking it up, and skipping all the stuff with the sweater and the drier, does sound interesting. Let's see how that works in part 2: switching characters during conversations.

Under the hood: room scripts and global scripts

Most of these glitches are based on the same idea: executing a room script when you're not supposed to.

So, what's a room script? And what's a script, for that matter?

A script is a series of actions the game does at certain points, usually in response to your own actions. For instance, when you first open the grandfather clock, at the beginning, the game responds by running script number 149. This script starts the cutscene where Bernard says "Ah-ha! A secret passage!". Or, when you use the tentacle chart with the flag patterns, the game responds by running script number 25. This script turns the flag into a tentacle.

Most LucasArts adventure games, from Maniac Mansion to Curse of Monkey Island, were written using the SCUMM engine. In SCUMM games, there are global scripts, and there are room scripts.

Global scripts usually involve sequences of actions across different rooms. For example, script number 149, mentioned earlier, starts in the lobby (Bernard entering the dark passage), then continues upstairs (Hoagie and Laverne meeting Dr. Fred), then it continues in a different room with Bernard freeing the tentacles, ... The important point about global scripts is that global scripts continue running when the action moves to a different room.

Room scripts, on the other hand, run only in the room you're currently in, and they stop immediately when you leave the room or you switch to a character who's in a different room. For example, if the chattering teeth are moving, and you leave the room, they'll stop moving, and they'll remain still until you enter the room again.

An important characteristic of room scripts is that they share the same names. In every room, the first room script is script number 200, the second room script is script number 201, and so on.

When running a global script, such as script 149, the game doesn't check which room you're currently in; there's only one script number 149, so the game runs it. On the other hand, when running a room script, the game does check the current room. For instance, when running script 200, the game checks which room you're in, and runs that room's first room script.

Here's an example. Let's say Dr. Fred is in his office, opening and closing the safe like a maniac. You go to the office, and you try to pick up the contract. When you try to pick up the contract and Dr. Fred is opening and closing the safe, the game runs room script 205. That script makes Dr. Fred close the safe, and then Bernard says "He almost took my hand off with the door!".

But what would happen if, while Dr. Fred is opening and closing the safe, you could try to pick up the contract while you're in a different room? For instance, but would happen if you tried to pick up the contract while you're in the kennel, in the future? Well, you can't, right? Because the contract isn't there to be picked up.

But, if you could, the game would run room script 205 in the kennel. In this room, script 205 makes Laverne give the dinner certificate to the guard. Even if Laverne doesn't actually have the dinner certificate! So that's what would happen. You would skip the whole beauty contest. If you could do it. But you can't, right?

Right?

Well, we'll see about that. Let's go down the rabbit hole, starting with part 2: switching characters during conversations.