I tried your game, here are random thoughts:
The download from itch.io was named lovegame.love (use real game name)
My first thought was "Oh, the music is bugged/skipping and repeating the same one second loop."
But now I opened menu2.mp3 and it really is like that.
At gamestart I pressed every possible key and nothing happend. Then I used mouseclick and it worked.
I think it would be good if spacebar, return, ctrl and other "common" keys also worked. It saves that tiny bit of frustration right at start that can make people close a game very quickly.
Gameplay itself is decent. Reminds me of Flappy Bird / "Fly the copter" (google it, it is old famous flash game) where you also only have one button to go up and gravity pulls you down.
In those flying games you can push yourself upwards at any time, in PigJig you can only jump when on the ground.
I think that makes the gameplay a bit more simple, maybe too simple? A bit like the Firefox-No-Connection game with the dino but you only play that for 20 seconds while you wait for WLAN to reconnect.
I understand that the simplicity of "one button" is
the thing about this game but maybe it would be cooler to have something extra. Like a double-jump ability. Or the longer you hold the key, the higher you jump.
The spitting mouthmonsters felt a bit pointless because I can not vary my speed anyway?
The red "ghost effect" on death is nice. Cool to see where you keep failing.
At one point in level 2 I was stuck in death-loop on a trampoline-thing. It spawned so many particles that the game started to lag.
From technical side it is of course impressive that a playable game can be made in such short time, with menu even.