The first thing any good level must have is a recorded solution! To record a solution for your level, simply press "R" from inside the level editor to make use of the hidden solution-recording feature. After pressing "R" you will have to use your keyboard to solve the level. As you solve the level, the game will record the time at which you press each key on the keyboard. When you reach the exit tube, the recording will stop and you will be returned to the level editor. To play back the solution you have recorded, press "P" from inside the level editor.

Remember to save your level, after recording the solution!

NOTE: If you make changes to the level after recording a solution, the solution may no longer work. Solutions record your keystrokes only, so if you make too many changes to the level, the recorded keystrokes will probably no longer be sufficient to solve the level! If this happens, you'll need to press "R" again to re-record the solution.

Work Backwards

One good technique for creating tricky levels is to start with a complex interaction, and work backwards from that. For example: Start out with the requirement that the professor must stand on a crate and shoot a Frost Gun into a trampoline to freeze a Rage-Bot which is blocking the exit tube. Then work backwards from here by moving the crate to some other location on the level (so that its true purpose is less obvious), and making it hard for the professor to reach the Frost Gun. You can even try to hide the true purpose of the trampoline by adding a mini-puzzle where the prof must use the trampoline to bounce a barrel.

However, you must be careful! Complex levels such as these can often be solved in many ways! You'll have to test your levels thoroughly to ensure that your intended solution is the only solution possible.

Subtraction

Try making a level with a number of elements, and a complex path to the exit. Then remove one of the elements (a powerup, for example) and see if you can still find a way to solve the level. If so, try taking away another element. Repeat this until you're certain that all remaining elements are required for the solution.

This technique often results in interesting and convoluted solutions. It takes a bit of practice to get it right, but the results are worth the effort!

Use the Hotkeys!

Well, hotkeys won't help you make better levels, but they may help you to make levels faster :) The list of level editor hotkeys is below:

1 - grass; 2 - sand; 3 - ice; 4 - ladder; 5 - 2x2 ice; 6 - 3x3 ice; 7 - 4x4 ice; 8 - 5x5 ice; 9 - 6x6 ice; 0 - eraser; - - level start; = - level end; z - metal pulley; x - wood pulley; c - crate; v - metal crate; b - barrel; n - left magnet; m - right magnet; , - let bot; . - right bot; / - trampoline;

F1 - frost gun; F2 - EMP; F3 - whistle; F4 - inflatable barrel; F5 - inflatable crate; F6 - inflatable magnet; F7 - blue gate; F8 - yellow gate; F9 - red gate; F10 - blue button; F11 - yellow button; F12 - red button

NUMPAD1 - dawn background; NUMPAD2 - day background; NUMPAD3 - dusk background; NUMPAD4 - night background

L - load; S - save; R - record solution; P - play back solution; G - toggle grid display

CTRL - constrain cursor movement horizontal; SHIFT - constrain cursor movement vertical

You can find the game here:
http://www.qweas.com/download/game/kids/professor_fizzwizzle.htm