Yes, I beat Happil 1.

Why?

I'm an idiot lmao.

Anyways, there is one impossible segment in stage 4 which prevents the game from being physically possible without modification. So I have modified the game to remove the impossible jumps in that segment, the nerfs are show in the video more clearly. Overall the game took me about 30 hours to complete, tho the hardest thing is by far the boshy/dark boshy boss which took 15 hours alone.

Stage 1: Pretty easy, just a few traps and easy platforming.

Boss 1: Pretty easy, the boss is slightly bullshit on the spikes attack but other than that it poses no real challenge.

Stage 2: Honestly a pretty interesting gimmick for the stage, not much of it is very hard and its also quite short.

Boss 2: Second hardest thing in the game, the boss is actually pretty fun aside from the bullet bills at the start, but the ending segment is pretty bs sometimes, its by far the hardest part of the fight.

Stage 3: Cool stage, platforming is pretty generic but the fall damage gimmick is kinda funny, the last save of the stage also has an invisible super f which is really bruh.

Boss 3: Good boss actually, my clear attempt had some crazy dodges on dispenser but its pretty fun to play overall.

Secret Stage 1: Funny idea for a stage, but the level 12 save has required low jumps in yosniper engine which is not a fun time.

Secret Boss 1: Easy boss, tho theres one attack that is like, actually so hard lol, the rest are fine.

Stage 4: This stage has an impossible segment on the second screen, which I nerfed so I could pass it, aside from that the stage is just a pretty generic VVVVVV stage, gravitron is cool.

Boss 4: Phase 1 is pretty good, I loved the original version of this boss and this one is pretty epic as well. Phase 2 sucks though, some of the rng is really bullshit, and the platforms on the ending section make literally 0 sense I don't fucking understand them.

Stage 5: Interesting stage idea, its like, fine for all of it even with the visual challenge, except for one save which is miles harder than the others for no reason.

Boss 5: Probably my favorite boss in the game, the gimmick is so good, you press C to freeze time or V to be invincible, you have to react to which one you need to use when he uses an attack, and you can also press CTRL to make the car appear that damages him for 10k damage. Very fun.

Secret Stage 2: Chill platforming stage, its kinda fun.

Secret Boss 2: Fun boss other than the bullshit falling saws and spikes.

Stage 6: Really odd stage, its IWBTG but with traps I guess?

Boss 6: First phase is incredibly bullshit, you just sit in the corner for the second guy and pray you dont die. Phase 2 is also bullshit but the blue guy dies a lot faster and the flying section is actually good but pretty easy.

Stage 71: Really short and easy stage, just some random guys pop out and then explode.

Boss 71: Luck based boss, you sit in the corner and hope he doesn't jump into you, helps if you can spam fast.

Stage 72: Short platforming stage, the first save I originally thought was impossible due to collision issues with the boshy spikes, but if you bhop when landing you can avoid this issue, this makes the save really hard though, but it is in fact possible, rest of the stage is easy.

Boss 72: Hard boss, there are some tricky patterns at the start, on the second phase though, the heads are hard to read but the platforms, literally make no fucking sense. The third section is pretty managaeable when you know the patterns.

Stage 81: Pretty fun stage but its basically just KTG lol.

Boss 81: By far the hardest thing in the game, took me 15 hours to beat and needed a lot of work on the practice tool to even have reasonable strats, incredibly unfair boss, you get walled so often lol.

Stage 82: First screen is really easy, the second screen one the pre last save has issues with collisions, and you have to cancel bhop to do the f jump, pretty hard.

Boss 82: Very good boss to finish off the game, has cool gustav elements to it, and it's not too hard, very fun overall.

And thats the entire game, not particularly good, but its rather interesting at least.

World first clear as far as i'm concerned.