I get that Sunky's a comedic character, but I think his implementation in SRB2 could have been handled a lot better.
The sprites are very basic with it only being sprite rips from the Sunky games which is kind of lazy if I'm to be honest. I'm not asking for a full custom sprite of Sunky, but knowing that there is a full model sheet of Sunky on Looneydude's twitter, I feel like there could have been some attempt at a full body rotation even with the base sprite still being from Sunky The Game.
His abilities are very limited and due to his slow walking speed and low jump height, it already makes it very difficult to beat Greenflower Act 1 without abusing the game's physics, which gives me the impression that he wasn't fully play tested with all the vanilla game's levels.
I think one way to combat Sunky's limited mobility would be to make use of his stretchy arms (seen in Sunky Part 1), and allow him to launch himself off of enemies or the terrain to gain the momentum needed to clear the levels. If you've played "Ristar", then my idea is essentially based off of that game. If that's going a bit too ambitious for SRB2, then you could make him pick up enemies to use as a boost (ala Klonoa, or Milla in Freedom Planet), and allow him to charge a super jump via crouching for a few seconds like in Super Mario Bros 2 (something that Sunky has been in via the April Fools "Sunky the Game 2").
A simple kick can only go so far for levels that were not designed for a heavy character like Sunky, you'll ideally want to work around it if you want people to enjoy the mod more than just the novelty of playing as Sunky for 2 minutes.