V1.0.1 - Bug fix release.

[Framework Changes]

• Simplified more scripts.
• Removed, descriptively renamed, and changed the scope of, even more variables and resources.
• Changed the gamepad connection check frequency to 10 seconds instead of 5 seconds.
• Removed the instance deactivation/culling controller object and placed its code in the End Step event of the stage controller.
• Removed usages of "roundto_unbiased" and "approach" for easier GM:Studio porting.
• Removed the "platform_offset" variable for moving/swinging platforms and rewritten vertical movement when standing on one of them accordingly.
• The pause menu is now destroyed whenever restarting a level or returning to the title screen; this allows for proper clean-up of the CPU-controlled player's inputs and the trail data structures.
• Added looping points for the background music in the Engine Test Zone acts.
• Implemented the Sonic 2 title card for the first Engine Test Zone act.
• The input queues for the CPU-controlled player are no longer initialized if there is no second player.
• You can now supply a mask to use for collision checking with the "main" sensors.
• Fixed most collision bugs with varying gravity angles.*
• Disabled the trail effect by default (it was odd to leave a "modern" feature enabled in a classic Sonic styled framework).
• Fixed a bug where the player's vertical speed would not reset when colliding with the bottom side of an obstacle or a ceiling that had its "ceiling movement" flag disabled (this was an oversight and not an issue in S8E or Harinezumi, my apologies).
• Rewritten underwater handling.
• Renamed the "skidding" state as the "braking" state.
• Fixed an issue where slope friction would always take effect, instead of only when moving like in the original games.
• Greatly simplified the formulas for air resistance and spindash charge atrophy.
• Fixed an issue where the camera would immediately snap to the player when they land; the camera will now slowly move towards the player.

  This new behaviour was in S8E, but S9E's camera rewrite was done using the current version of the "Camera" section of the Sonic Physics Guide; older versions of the page (which can be viewed in archive.org) mentioned the camera's slower movement towards the player upon landing.

• Fixed an issue where the player couldn't collide with the sides of monitors whilst jumping.
• Fixed an issue where if Tails collided with the bottom side of a badnik whilst flying, and he was not moving upwards, he could get hit.
• Fixed the player's collision with projectiles (this was in the initial release but was buggy and forgotten in the S8E => S9E changelog).
• Slightly changed the frame order of each characters' rolling sprites (except Tails) to be more accurate to the original games.
• Extended each characters' spindash animations (except Tails) and raised the spindash animation speed from 0.8 to 1 to be more accurate to the original games.
• Lowered the animation speed of Tails' tails when spindashing from 0.5 to 0.33 to be more accurate to the original games.
• Changed the rolling animation speed formula back to how it was originally in S8E.
• Tails' rolling animation speed is now the same as other characters', except it is capped at 0.5.
• Removed the rolling animation speed cap for all characters (except Tails, as mentioned above).
• Slightly shifted back Tails' tails when flying to be more accurate to the original games.
• Removed the animation frame modification of the "corkscrew" animation in the player's corkscrew handling script, and quadrupled the animation speed of the "corkscrew" animation for all characters from 0.05 to 0.2.
• Greatly simplified general animation direction modification (i.e. you face the direction you're pressing and moving towards).
• Updated the S8E => S9E changelog to include any new or missing differences, and to fix grammatical errors.
• Added usage terms for S9E.

[Gameplay Changes]

• Added Sonic 1's title emblem (credit to VectorSatyr) and the GHZ background to the title screen.
• Added Sonic 2's level select background for the options menu (credit to Tpot & VectorSatyr).
• Added a fourth screen scale.
• Pressing left/right in the options menu will now freely most toggle entries on/off instead of being restricted to a particular horizontal axis value.
• You can now hold down the left/right keys to decrease/increase audio volumes in the options menu periodically instead of repeatedly tapping them.
• Halved the input mapping buffer period from 0.5 seconds to 0.25 seconds.
• Added the "Data Select" caption from Sonic 3 to the Data Select menu.
• Removed duplicate character pair-ups from the Data Select menu slots as a result of the swapping feature.
• The player's score is now saved to whatever slot they picked in the Data Select menu instead of resetting every time a stage is entered.
• Removed the deceleration quirk while rolling to fix a bug where it would take effect whilst rolling in a tunnel.
• The player can now skid if they're pressing in the direction opposite of which they're moving towards; this is more accurate to the original games (credit to TsukiruP).
• Sped up the rate at which the dust effect is created whilst braking or sliding.
• Swapping characters now swaps their character index values internally; this allows for maintaining the current leader/follower into a new stage instead of resetting it based on the chosen Data Select slot pair-up.
• You can no longer swap with the CPU-controlled player, nor can they respawn, during the results tally if there is a configured level completion style.
• Fixed a bug where if a magnetized ring was destroyed outside of the view, it would create a dropped ring in its place.

The included test executable has been patched with DBGHelper to fix performance issues on modern versions of Windows (credit to omicronrex).

*NOTE: Tails' tails are positioned incorrectly and collision with springs do not work yet with varying gravity angles. I will fix both of these at a later date.

V1.0.0 - Initial release.

A test executable has been included which has been patched with DBGHelper to fix performance issues on modern versions of Windows (credit to omicronrex).