This was intitally made for a game jam, so some polish was been skipped to focus on making other elements of the game within the short time frame. But since I more recently decided to revisit this game, I am more willing to take a look at some of these. I might just need to pick your brain to figure out exactly what needs to be fixed. If you don't mind.
Funny enough, the wasd spam isn't a bug. Spamming keys to speed up was something I directly implemented into the game to speed up ice sliding for people who found the sliding too slow paced. A little reduant now that you can just toggle max speed on? Sure. But I thought people would consider it an Easter Egg rather than a bug. But the fact you assumed it was an issue is worth reconsidering if the mechanic is worth leaving in there. I'd be willing to remove it if people consider it problematic.
Though I'm not sure if I get what you mean by "lagging between levels". Like I'm not sure if you're referring to there being literal lag I'm not seeing, or if the screen transition is just so slow that it looks like like lag.
One of the rules for the game jam was that we had to have a fancy transition and use it for every screen transition. So I get that transition does make it take longer to go between levels, but I wouldn't want to remove it all together.
I'll take a look during my redevelopment to see if theres anything I can do. But if there's anything you can elaborate on with your lag issues, it would be appreciated. The better I can understand what you mean, the more likely I can "fix" it.
Hopefully I didn't chew your ear off too badly. Thanks for the feedback. I was just about to make a post that asked people to try it out and leave feedback like this.