Very cool!
The graphics are very nice, but I think the mario style bricks kinda clash visually with everytnig else. Maybe if they were also hand drawn and more soft looking?
You can sometimes make a doulbe or a triple jump? It involves spamming space quickly and never gets you any higher than a one long jump so it's not a big problem, but still a little weird.
I had some problems with getting into sideways in the pac man maze while wall jumping, I think you should be alble to change direction sooner after wall jumping to make this easier or maybe not be able to change direction at all to encourage players to find other solutions.
I really liked the creative use of mario pipes and the whole world orientation changing was cool, but having through that again got a little tedious. Maybe You could make another pipe that that just moves the player back to the "hub(?)"
The space invaders minigame had to be my favourite, but the pac man maze was also pretty fun and amost turned into a horror game haha.
Pretty fun little game. Overall good job!