Just played the demo for a bit - - FANTASTIC Jans!
I found myself drawn in by the character design - - BLINKY is appealing as a hero, and I feel compelled to help him, well done.
The physics feel good, although the edges of ledges seem "magnetic," and I discovered I don't have to precisely hit them, and get drawn in? Or maybe it is that the "edges" project out a bit invisibly? Either way, the edges are not quite where I expected them, but then I started compensating for or relying on that "invisible" or magnetic part.
On colors, I am not a fan of the yellow-green scheme on LEVEL 2. I prefer the red of level one, and have a second favorite of the blue on level 3.
The enemies are good, with a nice variation of types/challenges. I REALLY like how you have positioned various enemies in different spots, like the BOUNCERS right next to or on single brick widths, and then the parapets or "pits" on LEVEL 3 with the horizontal DASHERS is very fun!
I like how the gold nuggets are cumulative for extra lives, even between levels! Once I figured that out, I was encouraged to go for them more.
Like others have said, this is a GREAT game engine! You can choose to go a lot of ways with this! Some said "bosses" - - I think the levels are "boss" enough, personally.
Music, at least one simple melody that plays ocassionally (not all the time!) and some other background would be nice.
That's what I have for now . . . time to go try and beat LEVEL 3!