if you want to make the same modifications:
the level: https://mb.srb2.org/addons/sonic-robo-blast-2-the-past-version-2-0.4613/
the sonic version: https://mb.srb2.org/addons/past-trio.5603/
the HUD: https://srb2workshop.org/resources/halloween-doom-legacy-styled-hud.440/
As a reminder, this game, SRB2 (Sonic Robo Blast 2), is a Doom mod. Also, a derivative mod, SRB2K (kart) is one of the best freeware classic mario kart-likes in existence. The devs have moved on to Dr Robotnik’s Ring Racers, but SRB2K is the goat in my heart.