It's kind of hard to ruin a proven forumla like that of a jigsaw puzzle game, but some people manage to do it. The result is a mixture of half-baked ideas that could have been so much better.
Mixing an action minigame with the patience-driven puzzle game just doesn't work. It doesn't help that the Tower Defense-esque portion is mediocre at best. You have a single straight lane were a few Zombies at a time come out and you can either place barricades to slow them down, mines to kill them or shoot/throw grenades to kill them. One problem here is, that you get the money to buy this stuff not from killed zombies but at random for correctly places puzzle pieces another, that as soon as a timer runs out, more and more Zombies come down the lane and you don't have much time to concentrate on the actual puzzle anymore.
On the bright side, you don't have to play in this mode and can enjoy the puzzles taking all the time you want.
That would be nice, if the actual puzzle game would be good.
First the mechanics are totally off - it only checks the position of the tile against its right spot on the canvas and there's no possibility to connect tiles and move them around. Either you find the right spot and it gets locked or not. That's acceptable for minigames in larger games, but not for a standalone jigsaw game.
Finding the right tiles is made ridiculously hard with all of them floating and moving around the edge all overlapping each other and not respecting screen borders. The tiles are a fraction of their actual size and the elaborated shapes are barely visible. If you finally spot a piece you want, the game does its very best to make it as hard as humanly possible for you to actually grab it. Even if the cursor is right over it and it's not overlapped itself or overlapping you will most likely grab another, presumably warped in from the other side of the screen.
Apart from that the actual puzzles are too easy. The last one only has 350 pieces, the tiles can't be rotated and like mentioned before will just snap on get locked if they're in the right spot.
If you're on the brink of frustation due to chasing a tile for literally a minute, you will start to notice something else. The badly looped, too short single piece of background music, the clunky controls of the action mini game and the uninspired pictures themselves.
And then there is a third game within the game. The main menu is kind of a twin stick shooter zombies ... for whatever reason. But this comes with its own problems, like imbalances, weird hitboxes and a delay between triggering an action and the actual action, leading to you firing shots in whatever direction you're facing while it's performed and not the one where it it's supposed to go.
Oddly enough the developer honours that gimmick with a good portion of the achievements, one for surving 60min and one for killing 5000 zombies - in one life, in one sitting, without pause - which takes around 100min. The actual distinguishing feature of the game - the tower defense - meanwhile only gets a total of 3 achievements, one of them for failing. The elephant in the room: is this reflectory of their priorities for this game?
Anywho, if you enjoy jigsaw puzzles it might still be worth it for you. I spent around 6h on the 20 puzzles and did get some enjoyment out of it.