Cute idea and concept, but part of what makes the Mario games so good is nailing the controls. They need to be a lot more forgiving, as it is I keep falling from jumping a moment too late.
Scoring system completely messed up. As far as I can tell it gives one point per removed block and one point per click (no matter if the click removes anything or not). This means that there is no reason to try to clear big groups and just speedclicking like crazy is the way to get the most points. If removing 5 blocks instead gave 25 points (5x5) and there was a combo bonus for repeatedly not removing groups of 2 then this game would be a whole lot of more fun.
The game concept is ok, but the execution isn't the best. First off, the game feels slow. If you made pressing the right arrow key have the spinner accelerate to the right instead of moving to the right so that you could go in more than one speed if wouldn't have to feel so slow. Also, the big red arrow you need to click "Go!" with stays on the screen when the game starts. Why not just let me press space or so to start a level given that the game is keyboard controlled?
Too slow jumps. Add a timer and a score-box at the end of each level. Since the color order of the flags is the same each turn, why not just have numbered flags? Would make the game much more obvious to figure out for those that don't read rules... Also writing "Could be done better :(" at the end of levels is more discouraging than incouraging to try again. Instead give out "Ace score" or such on levels cleared quickly and just say "level cleared" on the others.
This game would be a lot more fun with about five colors instead. Unexpected combos is what make this type of games the most fun and trying to build a long combo while constantly being bothered by the automatically falling blocks was also near impossible. How about instead of having full lines of blocks falling down you just have blocks in a few column? Then you could increase the number of column the longer you play... This feels like it could be a good game though. I really like the way it was not game over directly when one column went over the line (though graying them out made it hard to see what types of pieces were in the line easily). I notice now that basically every suggestion I made is a way to make the game easier or easier to play and I think that is what a puzzle game needs to suck the players in is to feel really simple at the start and then start getting gradually harder.
I'm going to repeat what a few people have already said. The monster-lines dropped automatically need to remove things as well if they form groups. There are way too many monsters and having several of the same color but with different shape is always a bad idea in a puzzle game since many players will just think of them as being "yellow". This problem is made worse by the fact that the monsters you are about to drop fade up on a green background, making me repeatedly mistake one color for anyother since I just glanced on it while it faded up and then started scanning the board for matching colors. Puzzle games should feel like the rules are on your side, so when the lines drop they should do so slower than your pieces not faster. Also, the guys holding the monsters move too slow. Quickly pressing left-left should move them left two columns, not one.
Nice graphics and theme, but waaay too many colors of sap. Why not have about five colors and require that you match four instead of three and add some more problem types of sap to ramp up the difficulty. That way it would be possible to actually get some unforeseen combos and it would feel less like just bad luck when you get the wrong colors to set off your carefully built chain since it won't happen as often.
Two things need to change for this to feel like a fun game:
1) Needs to be harder. Add some sort of difficulty a bit into the game. Like a timer that drops the piece ready or not and then decreasing how long you have the longer the game runs.
2) Combos! What makes most tile dropping games fun is the possibility of making combos. If I have a column of (from down to up) 945 and drop 561 on it (with collect 10) I want the first the 5+5 to take out each other and after that the 4+6 and then the 9+1, taking in some extra combo multiplier score. Yes, I understand that this would make the game even easier, but that would give you the chance to add other things that make the game harder. Special tiles of some sort or tiles that are placed horizontally or made up by more than three pieces.
As it is, this isn't fun enough to keep playing to even see if it gets harder if I keep playing.
 "Enough Plumbers"){kind=icon}
 "Poclick"){kind=icon}
 "Marbyl"){kind=icon}
 "Straight Up Spinning"){kind=icon}
 "Ice World"){kind=icon}
 "Monster Dropper"){kind=icon}
 "Sap Refinery"){kind=icon}
 "Sumz!"){kind=icon}