There's a couple of gripes I have with this Sudoku game. First of all, I wish I couldn't see the possibilities for each cell. I wouldn't say get rid of it, but I would have it as an option to enable or disable.
My other complaint is that I have to use the game-pad of numbers and cannot use my keyboard to fill in the numbers.
If anything, this game feels like a demo. However, this feels like a very well polished, very entertaining, demo. I hope we see the other chapters to this game very soon! Just like others have said though; each chapter needs to be longer than this at the least. I personally played through multiple difficulties until I upgraded almost everything. It's that fun!
Another strategy I found for the last level is to build 3 of the Radio plasma towers in the #2,3,5 slots while building a decoy drone tower in the top and a time stop tower in the #1 corner. As ShangaZ has done, max out the time stop tower's recharge time first, then work on the freeze time. When appropriate, upgrade health on your plasma towers and timestop. I never invested in damage upgrade for the plasma towers; I maxed out reload times on all three towers and put the rest in health. Prioritize your targets and, with a few retries, you should be able to accomplish the mission.
I know others wrote this (This is simply to combine them), but here's some common tricky button solutions:
Soda Machine: Drag coins to slot... Hit the "coke" button... Click the red button... drag mouse to side of machine to "hit" button loose... then click on push and button
Praying Man: Simply click the man's reaching hand and a button will appear.
Christmas Lights: Drag each bulb to the strands according to the picture. When the bulb is in the correct spot, it'll snap into place.
Trash: Drag all items off the trash can lid, then drag the lid off, rinse and repeat to reveal button.
Egyptian: As many others said, just drag mouse off screen until the boulder does its' thing. Then drag each box to its' appropriate spot. Use the illuminated spot to reveal the red button (upper center) and center the light in order to click the button.
Drjaws's guide will help you for many of the early puzzles in case you get stuck. Please click the plus if this helped you.
 "Running Fred"){kind=icon}
 "AdVenture Capitalist"){kind=icon}
 "Free Online Sudoku"){kind=icon}
 "Tankblitz Zero"){kind=icon}
 "StormWinds 1.5"){kind=icon}
 "ButtonHunt 2"){kind=icon}
Thanks each part of trilogy will have 4 levels min.