I find the game's aesthetic cute with the whole Windows 98 thing. It's been donebefore but its still novel when it happens. I might play the game more later I got stuck in the first level and got a bit frustrated :-(
One thing I'd recommend is that wall jumps have you stick automatically without having to hold the button down when handling digital input as an easier fix for that. I found the wall jumps a little bit tough to do and I always overshoot and undershoot jumps. Other options may include having the character slide up a wall with momentum or having them jump up the wall rather than away from it.
I found the triangle enemy a bit hard to see with the gradient at some points. Perhaps giving them an outline would help solve that as well (or maybe having the enemies be this sprite)
Clippy's changing comments are cute and annoying (which I assume is the point). One thing I may consider is having is an audio cue when he says something different (even though I am aware it can break the authenticity) so that you know he's being sassy.
I really like that Clippy reveals you can expand the Window size. I thought that was really clever and cool. The music is alright. One thing I may have considered if I was doing a similar project was to have all the sounds used be based off Windows XP samples.
I will try playing the game more later on. I guess right now it just feels a bit too punishing due to the controls but the aesthetic of the game is really charming. I guess in the future if there's not enough time to properly playtest, its better to make the levels and game too easy than to be potentially too hard which was the approach I went.