Ahh level design. It's a subject that makes you excited and want to cry at the very same time. When you've got everything done in your game except for the levels it feels scary. Sometimes enough to make you procrastinate. I should know, I'm a professional procrastinator. I should get a certificate or something!
The key thing with level design is to make it challenging but not frustrating to the players. It's not easy though. I've made something like 10-15 level based games each with say 20-40 levels. That's around 300 levels in total, give or take 50. It's insanity to even think that I've made that many over time. Even though I've had so much practice I still fall into the old guilty traps every single time. I make levels too frustrating or difficult. It's why the The Unfair Platformer was so great for me because all I had to do was design levels like an asshole and people loved it. Do that in a normal game however is bad :P
First of your first levels are always the easiest to make as you can introduce each new type of feature in your game and make that the focus of the level. After that is when it starts to get tricky. A general goal is to make the puzzle seem obvious to solve but they need to work out how. This gives people a sense of reward when they work out a goal from start to finish. If you make it so they need to guess too much they will feel they are doing something too random.
Stuck for level ideas? Try these tips
- Base an entire level on a particular feature
- Put the start and end close together and make them do a full circle of everything to get back
- Make them use a specific game feature in each area so it becomes more useful as time goes on
- Make the last level really hard, and the first level really easy. Then work in between for a difficulty curve.
- Make a big object in the middle the level focus's on that interacts with everything
- Get friends to have a go making a level, maybe make a level editor.
- Play level based games in the same genre to get ideas.
- Drink 99 cups of coffee till life seems like a level and draw it (just kidding... or am I)
- Filler levels can expand on earlier levels with adding in more enemies on the same puzzle
These are some general tips to pump out some levels. The more you make and the more games you play you'll start to see general patterns in game design on what levels are used often. It's when you're past the first 10 levels you really can show how smart you are as a game designer to come up with intricate traps that really make them think without pushing them to anger. It's not easy. What may seem easy to you, will be hard to someone else as they haven't made the game from scratch like you so it won't come naturally so be careful and have a lot of people test the game.
Good luck, level design is a science as much as an art. So experiment with lots of ideas.