Sonic Robo Blast 2: Official Level Design Collab 2023 - Round 2

Parent game

Sonic Robo Blast 2, abbreviated as SRB2, is a fan game for Windows and DOS platforms. It is a 3D platformer developed by a group called Sonic Team Junior, using a modified version of the Doom Legacy source port of Doom, to allow for such things as optional analog control and true room-over-room (something not possible in the standard Doom engine), as well as the standard gameplay elements Sonic games are known for. It has been in the works since 1998 and is currently nearing completion, though several parts of the game are still missing. Sonic Robo Blast 2 is closely inspired by the original 2D Sonic games for the Genesis and attempts to recreate a game with this style in 3D, though it also borrows elements from the current Sonic games, such as Sonic's signature Air Spin Attack. Entirely original to SRB2 is its Multiplayer mode, a variation of classic first-person shooter games with Sonic elements. Due to being built with a modified Doom Legacy engine, the game is also very easily customizable. Custom levels, characters and even source code modifications can be created with the help of external editors.
Could be interesting

Sonic Outbound is a Sonic fan-game set one year after Sonic Mania's bad ending where Robotnik had the Phantom Ruby and Chaos Emeralds in possession. After the final battle in the core of the Titanic Monarch, Robotnik was stuck in Little Planet and started collecting the Time Stones and preparing his greatest plan yet.

A 2D Sonic the Hedgehog fangame made with Clickteam Fusion

The world is a chaotic, terrifying place, rife with all manner of monsters, warlords and hostile architecture. Even for the mighty Pachacamac clan, just the act of survival is a day to day struggle, and everybody seems to know that they can't keep it up forever. In pursuit of a safe home, a lone shaman named Ichima happens apon the Special Stage - and with it, a means of realizing their dreams of safety and peace...

When Eggman opens a portal to Scuttle Town from Mobius, Sonic must chase him and stop him from taking over Shantae's world. With both worlds merged, Sonic and Shantae must find the Chaos Emeralds and stop Eggman and Risky from taking over the dimensions.

Sonic: After the Sequel - Omega is fan-made enhanced version of Sonic: After the Sequel.

A Sonic game introducing fast paced combat with limited open world areas involving story progress scenarios and side missions.

Sonic Chaos is a fan game and re-imagining of the 1993 Sega Game Gear and Master System platform game of the same name. Based on the current style of 2D classic Sonic games inspired by Sonic Mania, Sonic Chaos updates the 8 bit visuals of the original and adapts a play style more closely resembling the classic 16-bit games.

Sonic Time Twisted is an open-source Classic Sonic style fan-made game, headed by Overbound. The game tries to improve upon the best features from Sonic the Hedgehog CD and the other Genesis/Mega Drive games. These features including time travel, elemental shields, and 3D special stages. The player controls Sonic and co. and they play like they do in the Genesis titles. Like in Sonic the Hedgehog CD, the player must use time poles (now adjusted to be instant) to travel through two different time zones, Past and Future. In the Past, Sonic must find the Special Stages and collect the Time Stones, while in the Future, Sonic must also find the Special Stages, however, these have the Chaos Emeralds. Beat all 14 Special Stages in each time zone (7 each) and the player will achieve the True Ending. Besides that, the player must traverse through 8 zones, most with 2 acts each, reach the Goal Post at the end, as well as encounter a boss at the end of the stage be it Metal Sonic or one of many loyal Super Badniks.

Enjoy this fangame in 2d at full speed and platform. Eggman plans to attack with his air fleet and so that sonic and tails do not bother them he will teleport along with the Chaos Emeralds to places of the past.

This game is an experimental 3D platformer with weird references and other random stuff.