Castelian (NES)/Game Mechanics - Revision history

Ktwo: /* Alternative door exits (found by 'pirohiko') */

2024-11-09T09:10:22Z

‎Alternative door exits (found by 'pirohiko')

Ktwo: /* Glitched tower */

2023-10-02T16:38:46Z

‎Glitched tower

Ktwo: /* Glitched tower */

2023-01-27T08:24:04Z

‎Glitched tower

Ktwo: /* The molecule */

2023-01-15T20:41:37Z

‎The molecule

Ktwo: /* Alternative door exits (found by 'pirohiko') */

2023-01-15T17:42:41Z

‎Alternative door exits (found by 'pirohiko')

Ktwo: /* The molecule */

2023-01-15T17:41:14Z

‎The molecule

Ktwo: /* Enemy movements */

2023-01-15T10:49:52Z

‎Enemy movements

Ktwo: /* RAM-addresses */

2023-01-15T10:37:28Z

‎RAM-addresses

Ktwo at 20:40, 11 November 2022

2022-11-11T20:40:14Z

Ktwo: /* Enemy movements */

2019-08-17T12:56:57Z

‎Enemy movements

@@ Line 46: / Line 46: @@
 ==Bugs/tricks/glitches==
 ===Alternative door exits (found by 'pirohiko')===
-In towers 1-6 and 8, one of the doors has two different exits (the reason for tower 7 being excluded is because there are no doors in that tower). The regular exit is reached by the standard method of pressing up on the d-pad when in front of the door. The alternative exit is reached by instead entering the door by pressing down. Most of the alternative exits work as shortcuts, but not all. See the routing videos for more details about the considerations for the individual towers.<br /><br />
+In towers 1-6 and 8, one of the doors has two different exits (the reason for tower 7 being excluded is because there are no doors in that tower). The regular exit is reached by the standard method of pressing up on the d-pad when in front of the door. The alternative exit is reached by instead entering the door by pressing down (J-version) or B+up (U-version). Most of the alternative exits work as shortcuts, but not all. See the routing videos for more details about the considerations for the individual towers.<br /><br />
 The reason for some doors having two exits hasn't been investigated. Remains from the development process that were never removed or intentional secrets/shortcuts?<br /><br />

@@ Line 51: / Line 51: @@
 ===Glitched tower===
-At the top of every tower, there is one tile that when pressed down on will make a new elevator appear. Taking this lift will freeze the time (as well as the molecule timer) and bring you to a moderately glitched extension of the tower. By taking the lift back down, the tower can be completed as normal. While this has the potential for creating shortcut opportunities, it's not the case and none appears to be useful in a speedrun.<br /><br />
+At the top of every tower, there is one tile that when pressed down on will make a new elevator appear and all enemies to despawn. Taking this lift will freeze the time (as well as the molecule timer) and bring you to a moderately glitched extension of the tower. By taking the lift back down, the tower can be completed as normal. While this has the potential for creating shortcut opportunities, it's not the case and none of the lifts appears to be useful in a speedrun. However, despawning the enemies can save time and be used in a speedrun (e.g. in tower 5).<br /><br />
 The score is increased normally when moving up to the glitched tower top. In tower 7, there is even an additional glitch that let's you score points repeatedly by going up and down the glitched portion of the tower. Since time is frozen, it's therefore trivial to score an essentially infinite amount of points without any risk. This game is therefore not suitable for score attacks. However, a casual player or one in the process of learning how to speedrun the game could benefit from this by stocking up on lives before tower 8.<br /><br />

@@ Line 51: / Line 51: @@
 ===Glitched tower===
-By pressing down in front of the end door of tower 8, a new elevator appears to the left and can be used to reach above the regular top of the tower. The next level appears slightly glitched though and further advancement is not possible.<br /><br />
+At the top of every tower, there is one tile that when pressed down on will make a new elevator appear. Taking this lift will freeze the time (as well as the molecule timer) and bring you to a moderately glitched extension of the tower. By taking the lift back down, the tower can be completed as normal. While this has the potential for creating shortcut opportunities, it's not the case and none appears to be useful in a speedrun.<br /><br />
-It's difficult to see how this would ever be useful in a speedrun. But if someone were to attempt a serious score attack of this game, climbing higher than what's intended will score some additional points.<br /><br />
+The score is increased normally when moving up to the glitched tower top. In tower 7, there is even an additional glitch that let's you score points repeatedly by going up and down the glitched portion of the tower. Since time is frozen, it's therefore trivial to score an essentially infinite amount of points without any risk. This game is therefore not suitable for score attacks. However, a casual player or one in the process of learning how to speedrun the game could benefit from this by stocking up on lives before tower 8.<br /><br />
 ==RAM-addresses==

@@ Line 42: / Line 42: @@
 ===The molecule===
-Whenever there are less than four enemies active in memory and the molecule is not one of them, a timer counts down every game frame (= every 3 actual frames). At the start of the level, the timer starts at 125 (decimal), but will then reset to 255 after the first appearance. When it reaches -1, the molecule will spawn.<br /><br />
+Whenever there are less than four enemies active in memory and the molecule is not one of them, a timer counts down every game frame (= every 3 actual frames) from 125 (decimal). When it reaches -1, the molecule will spawn.<br /><br />
 ==Bugs/tricks/glitches==

@@ Line 46: / Line 46: @@
 ==Bugs/tricks/glitches==
 ===Alternative door exits (found by 'pirohiko')===
-In towers 1-6 and 8, one of the doors has two different exits (the reason for tower 7 being excluded is because there are no doors in that tower). The regular exit, which is reached by the standard method of pressing up on the d-pad when in front of the door. The alternative exit is reached by instead entering the door by pressing down. Most of the alternative exits work as shortcuts, but not all. See the routing videos for more details about the considerations for the individual towers.<br /><br />
+In towers 1-6 and 8, one of the doors has two different exits (the reason for tower 7 being excluded is because there are no doors in that tower). The regular exit is reached by the standard method of pressing up on the d-pad when in front of the door. The alternative exit is reached by instead entering the door by pressing down. Most of the alternative exits work as shortcuts, but not all. See the routing videos for more details about the considerations for the individual towers.<br /><br />
 The reason for some doors having two exits hasn't been investigated. Remains from the development process that were never removed or intentional secrets/shortcuts?<br /><br />

@@ Line 39: / Line 39: @@
 ===Enemy movements===
-The movements are predictable with one exception. There is some variation to the initial x-movement of the destroyable ball enemies. The movement of these enemies seem to be triggered according to a few different mechanics. For example, balls that spawn during a lift ride always (?) start moving immediately. There is one important mechanic that governs at least some of the other balls. Notably the one near the end of tower 4. The game then polls every 10 movement frames (so every 30 actual frames + any lag frames) whether to start moving the ball or not. The game then checks that the player is within 32 x-pixels, that it's on the same y-level and that the player is walking or standing still (so jumping or shooting will not trigger the ball). The sub-routine for this check starts at $D20B and a successful check results in changing the value of $15F+Y, where Y is enemy number (from 0 to 3), to a non-zero value.<br />
+The movements are predictable with one exception. There is some variation to the initial x-movement of the destroyable ball enemies. Some balls immediately start moving in the x-direction upon spawning (e.g. the balls at the very end of towers 4, 5 and 7). The other balls are triggered by various checks. The game polls every 10 movement frames (so every 30 actual frames + any lag frames) whether to start moving the ball or not. This corresponds to the ball being at floor level (the balls bounce up and down in a cycle of 10 game frames). The game then checks that the player is within 32 x-pixels and that the player is walking or standing still (all other player movements/animations will prevent the ball from triggering). These checks start at instruction $D20B and a successful check results in changing the value of $15F+Y, where Y is the enemy number (from 0 to 3), to a non-zero value.<br />
-It should be noted that there appears to also be balls following other mechanics that are not described here.
 ===The molecule===

@@ Line 57: / Line 57: @@
 ==RAM-addresses==
-A/122 - x/y of the main character<br />
+B0/B2 - x/y of the main character<br />
 /12B - x/y of enemy #1<br />
 /12C - x/y of enemy #2<br />
 /12D - x/y of enemy #3<br />
 /12E - x/y of enemy #4<br />
-- molecule timer <br /><br />
+- molecule timer
-The y-coordinates for the main character are different from the ones for the enemies, but this has no other effect than being a slight inconvenience from a practical point-of-view. (The main character's actual x- and y-positions appear to be stored in B1 and B3, but at least in FCEUX 2.1.4, B3 doesn't display correctly in RAM watch)