# How to increase difficulty of a catching game

I'm developing a game where products fall from the sky, and you need to catch them. A bomb also falls, and if you catch it, you die.

I have 3 different products with 3 different scores.

I want the game to get harder as time passes, but if I start incrementing the amount of bombs appearing, there comes a point where only bombs appear.

How can I increase the difficulty of this game without falling into a state with only bombs?

• First of all, punish the player for missing multiple objects in a row, so they can not just ignore objects that seem difficult to catch.
• Increase the falling speed and frequency, so the player needs to react faster.
• Come up with more interesting falling patterns. Like objects which fall at an angle or in a curve. This increases the cognitive load for the player.

You can define the chance to spawn an object and a chance to spawn a bomb into a percentage. As the game progresses you can increase the percentage for bomb spawn while decreasing the percentage for object spawn. This way you will be able to control your gameflow without worrying about not spawnning objects and being able to cap the percentage of bomb spawn. I don't know how to implement the system in code, you're going to have to figure it out yourself, but a good place to start is an article on lootboxes, as they deal with percentages. Link for the first article: https://medium.com/@guilhermegm/unity-simple-loot-system-d181220e6542/.

How about instead of increasing the number of bombs, try changing the bomb size. Larger bombs would occupy more space to make it harder to dodge and smaller bombs would take less space but fall quicker This way players would need to decide whether timing their movement to catch a product or ignoring a product covered with a bomb, would be better. You can do this by simply offsetting the sprite, collision size, and falling speed.
Make sure to place a minimum and maximum range when doing this.

You can use a weighted random. That means that you assign a weight to each possibility… Then to compute the probability of one of them, you divide its weight by the sum of all weights.

See How do I create a weighted collection and then pick a random element from it?.

Thus, you would be able to make one possibility (e.g. generating a bomb) more likely by increasing its weight, without reducing the weight of the others. This way their probability would never reaches zero.

By the way, a pretty old trick to increase difficulty is to make the game go faster.

Addendum: An alternative to increase the difficulty by making bad things more frequent, is to increase the difficulty by making good things less frequent. For example, if you introduce power-ups, you can make them progressively less frequent. Some power-up ideas:

• Reduce speed
• Invulnerability from bombs
• Score multiplier