NothingDoor 9+

If you’re stuck on a level, there are 2 main tricks to the logic.

1. Consider parity, the parity of a number is whether it’s even or odd. The end state of a level is when all numbers equal 0, which for this purpose is even.

Enemies with odd parity must be paired with weapons of odd parity, otherwise there is no way to reach exactly 0.

2. If robots and/or wands are present, count the number of enemy hit points and weapons. A health point or potion represents a positive number, death points and swords represent negative numbers.

For robots, take the number you end up with when adding everything together, and sacrifice that number of weapon points.

For wands, take the number you end up with and divide it by 2, that is the number of health or death points you must swap.

These tricks solve the majority of the levels once you understand them, though there are a few levels which require additional math to be done with the wands considering how much you swap with a given wand in respect to the total swap amount required.

I’m a math enthusiast, so I got this game when it went on sale, and I enjoyed it a lot! In the earlier levels, it’s about using your items in the right order and on the right enemies to cancel everything out, using the principles of a + (-a) = 0 and -1a = -a. Then, you start throwing away items that would otherwise keep you from that goal, and storing items to use later. It’s a great game with a fun concept! My only complaint is that the game felt a bit too easy, and also a bit too short. Maybe it’s just me, but even in the levels where I got stuck, it wasn’t for too long. Maybe I was stuck for three to five minutes on some of the more difficult levels. I’m pretty sure I finished the entire game in less than half an hour, if that. I’m not sure if it’s a bug, but when you go back to the level select, you can’t re-enter the level you were just at. You’re only able to enter the farthest level you’ve cleared, meaning that sometimes I’d quit by accident and have to redo the previous level to get back to where I was. Overall, it’s a very fun game that uses basic addition and puzzle solving skills, but I would definitely love to see some more challenging levels.