Instructions in-game would be nice. Also, something that registers if you have spikes around and monster and not wasted any, that does a prompt for solving the puzzle. And a generator, that doesn't produce levels that are already solved (spikes placed around the monsters, and have none wasted).
Of course, I understand that this is a prototype, but just giving helpful feedback.
Nice game of Solitaire. Not sure why you added the leveling system. There is no purpose in this game for getting higher levels, so it seems pointless to the player to have it.
If you had say X level unlocks new card faces or background, then that would work. But try to have a prompt that doesn't stop the player from continuing (like a pop up in the corner or transparent letters saying "Level X") or do it after the game is finished.
I have a lot of lag as well, but it is most likely due to using a laptop.
Has anybody found a way to drop the quality of the game? That should help with some of the lag issues people are having. If not, developer, can you implement something that can decrease the quality?